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THE 



EARTH 



ROBERT MUDIE, 



AUTHOR OF" 



THE HEAVENS, "THE SEA,' " THE AIR," ETC., ETC, 






PHILADELPHIA : 

CAREY, LEA, AND BLANCHA-RD. 

1836, 






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PREFACE. 

r 

Both the size and the purpose of this work 
are incompatible with the notion of its being a 
detailed description of the Earth, or a particular 
exposition of any one of the many sciences into 
which it is found necessary to divide anything 
like a thorough knowledge of our planet. The 
first of these must be sought for in the common 
works on descriptive geography, and the second 
lie scattered through the many volumes in which 
the doctrines of physical science, and the inves- 
tigation and description of physical agencies and 
their effects, are treated. To have attempted to 
embody one of those sciences would have been 
attempting to do anew that which has already 
been more fully, and therefore more perfectly, 
done, than if every page of the following sections 
had been devoted to it. To have drawn up a 
mere list of those sciences and their subjects, 
would have been presenting feeble-itovigs instead 
of the bundle of rods, and without *that cord of 
unity to which alone the strength of the bundle 
is owing. 

Therefore, I have attempted to supply that 
which is not found in any one book, and probably 
not in any number of books, which have been 
hitherto published. I have attempted to give as 
clear and comprehensive a view as possible of 
the earth, considered as a whole, having equal 
regard to the causes or agencies which produce 



4 PREFACE. 

the more general terrestrial phenomena, and to the 
things in which, and the places where, these phe- 
nomena present themselves. For this purpose I 
have first attempted to show the great practical 
advantages which are derived from a proper 
knowledge of the earth, and the characters and 
relations of the several seas and lands of which 
its surface is composed. I have next attempted 
to show the great assistance which we derive 
from a really good map of the world in learning 
those details that form the basis on which the 
more argumentative and inferential part of the 
subject is founded. Having done so, I have cast 
a glance over the various lands, and the seas by 
which they are separated ; pointing out the ge- 
neral character of each of the great natural divi- 
sions of the land, and hinting how these work 
together in bringing about all that occurs by 
natural causes. This being done, I have given 
some account of the agents and instruments which 
are chiefly influential in producing terrestrial 
phenomena ; and I need not apprise any one who 
is acquainted with the subject, that the grand 
agent is the sun, and the grand instruments are, 
the air of the atmosphere and the water of the 
sea, whiclmd-istribute the solar action over the 
surface of the earth, producing a state of things so 
very different from what would be if the air and 
the waters were as locally chained by gravitation 
as the more solid parts of the globe. 

In treating of solar action, and its distribution, 
which form the grand elements of a proper un- 
derstanding of the earth as the field of growth 
and the abode of life, which is the true and the 
useful understanding of the matter, I have thought 
proper, and have, indeed, felt it necessary, to 



PREFACE. o 

proceed something in the way of analysis ; and 
if, in the course of this analysis, one or two views 
have been opened up of the power and grandeur 
of some of the instruments of God's working 
which are new to the reader, he must not be 
startled at the vast height and the immensity of 
distance to which they beckon him to look ; for 
we may rest assured that, in all cases where we 
can carry our analysis of nature as near as we can 
to the primal secondary cause, the mind feels 
itself trenching upon the bourne of infinitude, and 
our philosophy falls down in humble adoration 
before the throne, confesses its Maker, and exults 
and triumphs in the confession. 

With a view to simplify this very sublime and 
very important matter as much as possible, I have 
first considered what would be the general effect 
pf the sun upon a hemisphere of the earth, if both 
sun and earth were at perfect rest, situated at the 
same distance from each other as they are now, 
and if the sun-beams had precisely the same na- 
ture as they have at present, but that there were 
no moveable air or water, or any marked differ- 
ence of surface, to modify their action. This is 
the elementary view, and the determination of it 
is a matter of geometry, partaking of all the 
certainty of that science ; and this being once 
understood, the observed departures from it of 
themselves lead us to the investigation of their 
causes. 

The full statement, or even the mere enume- 
ration of all those causes, more especially the 
local ones, would have been incompatible with 
the space to which I was necessarily restricted ; 
and therefore I have considered chiefly the two 
general sources of modification, — the daily rota- 
1* 



O PREFACE. 

tion of the earth upon its own axis, and its 
annual motion round the sun in its orbit. By 
means of these, I have been enabled to state ge- 
nerally the effect which is produced by the 
reciprocal actions of the two hemispheres upon 
each other at different seasons of the year; and 
also, how those actions are farther modified by 
some of the more remarkable characters of the 
extensive divisions of the land ; and thus I have 
been enabled to give a sort of general view of the 
phenomena of the year, though I fear it will be 
found both hasty and incomplete. My object is 
not, however, to teach scholastically, but to entice 
the reader to learn for himself practical!}^ plea- 
santly, and profitably ; — to stimulate the desire of 
knowledge, and to simplify the means of acquiring 
it, as well for the satisfaction and superiority 
which true knowledge gives us in this world, as 
for the confirmation which it affords of the fulfil- 
ment of our best hopes when to us this world shall 
be no more. 

Robert Mtjdie. 

Grove Cottage, Chelsea, 
August, 24, 1835. 



ANALYSIS OF THE CONTENTS. 



SECTION I. 

PRELIMINARY REMARKS. 

Advantages of a Knowledge of the Earth — Extent of that 
Knowledge — Method of studying complicated Subjects — 
Collateral Sciences- — Geography, Geology, Meteorology — 
General Instruction from the subject .... p. 11 — 30 



SECTION II. 

GEOGRAPHICAL REPRESENTATION, OR MAP, OP THE EARTh's 
SURFACE. 

Representation of the Earth — Globes — Maps — Stereographic 
Projection — Advantages of this Projection — Positions on 
the Globe— The Hemispheres — The Details — Uses of the 
Map,— In History, in General Knowledge . . p. 31 — 44 



SECTION III. 

FORM, MAGNITUDE, AND GENERAL FEATURES OF THE 
EARTH. 

Figure of the Earth — Irregularities of that Figure — Different 
means of ascertaining these — Distribution of the Zones — 
Advantages of this Distribution — Extent of the Earth's 
Surface — Relative Portions of Sea and Land — Comparison 
of the Two Hemispheres, as divided by the Circular Boun- 
daries of an Ordinary Map of the World — Northern Coasts 
of Asia and Europe — Characters of the Countries there — 
"West Coast of Europe — The Mediterranean, and its Basin 
— General Characters, and Action of this Basin — Seasonal 
Migration p. 45 — 80 



ANALYSIS OF THE CONTENTS. 



SECTION IV. 

GENERAL FEATURES OF THE EARTH. EASTERN CONTINENT 

CONTINUED. 

Northern Africa — Mountains of Atlas — The Desert of Sahara 
— Character and Action of this Desert — Progress of Ruin — 
Formation of Sand Banks — Decomposition of Mountains — 
Antiquity of the Earth — Ancient Egyptian Temples and 
Statues — Antiquity of the Desert — Comparison of the 
Wild and the Wilderness — Western Africa — The Fertile 

Country there — Flooding of Rivers — Southern Africa 

Eastern Africa — Southern Asia — Australia — Reciprocating 
Action between Southern Asia, and Africa and Aus- 
tralia , p, 81—110 



SECTION V. 

CENERAE FEATURES OF THE EARTH. AMERICA. 

North America — Its Boundaries and Divisions — The Great 
Central Valley — The Mississippi — Vegetables and Animals 
of the Mississippi Valley — Other Regions of North America 
— Mexico — The Table Land of Mexico— The Progress of 
Drought — The Mexican Andes — The Isthmus, p. 1 1 1 — 128 



SECTION VI. 

GENERAL FEATURES OF THE EARTH. AMERICAN CONTINENT 

CONTINUED. 

General Characters of South America — The Andes — And 
other Mountain Ridges — The Amazon and its Valley — 
The Orinoco — La Plata — Plains of Paraguay — The 
Pampas p. 129—147 



SECTION VII. 

BRIEF ABSTRACT OF THE EARTH'S FEATURES. 

Recapitulation — Interruptions of Sea and Land— Instances of 



ANALYSIS OF THE CONTENTS. 9 

those Interruptions — In North America — Tn South America 
— in the Eastern Continent . . . . . . p. 148 — 155 



SECTION VIII. 

ARESTS .\SD IKSTRUMESTS IN THE MORE GENERAL PHE- 
NOBEE-ITA OF THE EARTH. 

Duty of a Popular Writer — Advantages of Popular Writing 
on Scientific Subjects — The Natural Desire of Knowledge 
— The Relation between Action and Resistance — Aggrega- 
tion as opposed to Gravitation — Action of the Sun — Prin- 
ciple of Growth — The System of Matter — Swiftness of 
Light — Of Thought — Action of Heat — Seasonal Action — 
Action of the Air — Action of Air on Water — Effect of 
Motion in the Sun-beams p. 156 — 1S8 



SECTION IX. 

MODIFICATION OF THE St's's ACTION BY THE FIGfRE OF 
THE EARTH. 

Means of estimating the Sun's Action — Temperatures of 
Different Latitudes — Advantages of the Spherical Form of 

the Earth — Atmospheric Modifications of Solar Action 

Refraction — Reflection — Colour — Atmospheric Refraction 

— Partial Reflection Sun-beams on Water On Rich 

Surfaces — On Bare Surfaces — Grandeur of Creation 

p. 189—206 

SECTION X. 

EFFECTS OF THE EARTh's ROTATION. 

General Effect of the Earth's Rotation — Looking at and 
Looking from — Comparison of Rotation and Rest — Advan- 
tages of Rotation — Comparison of the Earth and Moon — 
Compound Motions — Motion in Rotation, and in Latitude 
— Air moving to the Equator — Moving from — Causes of 
Motion in the Air — The Sun over the Equator — Characters 
of Different Latitudes in this Case — Illustrations 

p. 207—244 



10 ANALYSIS OF THE CONTENTS. 



SECTION XI. 

MODIFICATION" ARISING FROM THE EARTH'S MOTION IN 
ITS ORBIT. 

Explanation of the Earth's Position in Motion — Effects of 
this Position — Change of Declination — Sun over the Tropic 
— Change of Motion in Declination — Heat on the Tropic 
— Apparent Annual Motion — Tropical Seasons — Recipro- 
cal Action of the Hemispheres — Tropical Vegetation — 
Palms — Northern Winter — Icebergs — Action of the Broad 
Lands — Monsoons — Seasons— -Studies which may follow 
that of the Earth— -Conclusion 245—286 



THE EARTH. 



SECTION L 



PRELIMINARY REMARKS. 

The globe which we inhabit, of the dust of 
which we are formed, and to the dust of which 
each and all of us shall one day be gathered, is 
not only an important portion of the material 
creation, but, to us who dwell upon it, it is by 
far the most important. The other portions of 
created matter to which the general name of " the 
Heavenly Bodies" is given, and of which a short 
popular account will be found in our correspond- 
ing volume, "The Heavens," have much of 
grandeur and sublimity in them, and inspire not 
only him who contemplates them with the eye of 
knowledge, but the most ignorant and untutored 
of the human race, with feelings of wonder at 
their magnitude, and of reverence for their 
Maker, which it is as difficult to describe as it is 
impossible not to feel. But to our knowledge, 
the grandeur and the glory of the material heavens 
is a tale which is soon told : when we have mea- 
sured them with the line, weighed them in the 
balance, ascertained their magnitudes, their shapes, 
their quantities of matter, the times of their rota- 
tions upon their own axes, their distances from 



14 PRELIMINARY REMARKS. 

great bulk of mankind, and becoming every day 
more and more closely linked with practical 
usefulness. 

It is impossible fo view this progress, or look 
forward to this result, without feelings of the 
most delightful description ; and here we have 
this consolation, that hope and philosophy go 
hand and hand in the matter. It is no vain dream 
of an over-fervent fancy, no mist-formed spectre 
of the distempered mind, asserting without proof, 
and concluding without data ; for we have only 
to look at the world, and, on whatsoever spot of 
the map our eye may alight, the impress of 
active improvement is clear and legible upon it. 

It is somewhat of a proud boast to us of these 
kingdoms (a national pride is an honest pride 
when the direction of it is the good of all nations) 
to have been, if not the very foremost, at least 
the most energetic, in thus awakening the world 
to its own welfare ; and when we behold the 
nations of the east, and of the west, of the north, 
and of the south, labouring with all their energies, 
and with every prospect of success, in bringing 
the ends of their several countries together, and 
uniting state with state, by means of improved 
river navigations, and canals, and railways, and 
steam-ships and carriages, — we cannot, nor need 
we, refrain from a little exultation, that these are 
the imperishable monuments of our Watts, our 
Smeatons, our Kennies, our Telfords, and our 
Nimmos. And there is a profitable lesson to 
ourselves in this exultation : for it was because 
these men grasped the volume of science with the 
one hand, and the necessities of mankind with the 
other, incorporating them with giant strength, 



PRELIMINARY REMARKS. 15 

that this world of the wonders of man's working 
was given to us. 

Nor is it upon a few individuals thinly scattered 
that this impulse has come. It has taken hold 
alike of rulers and of nations. Either because 
they have become wearied and worn out with 
wars, or have gotten wiser, we find that a spirit 
Is abroad, as well in the Mahometan world as in 
the Christian, though to different extents in dif- 
ferent places, in consequence of physical, and 
social, and moral, and religious differences, which 
we are not called upon to investigate ; and in 
consequence of this spirit the desire seems now 
to be, not to divide and conquer mankind, but to 
overcome and conquer those natural obstacles by 
which their peaceful and profitable intercourse 
with each other is impeded. 

When we look upon the map of the world, and 
behold those chains of gigantie mountains upon 
whose snow-elad summits the continual strife of 
the elements elaborates that humidity which wells 
out in countless thousands of springs, seams the 
mountain slopes with deep ravines and brawling 
torrents, the action of which lays bare to man 
more of the internal structure of the earth than 
could have been disclosed by the labours of the 
\vhole human race ; when we behold those rills, 
as they descend to the habitable parts, uniting 
themselves into streams equally ornamental and 
useful, equally efficient in aiding the labour of 
man, in the growth of materials, and in the turn- 
ing of those materials into all that is necessary 
for man's most comfortable subsistence ; and 
when we behold these uniting their waters again 
and again, until at last, through the regions of 



16 PRELIMINARY REMARKS. 

greatest fertility, and in some instances for full 
two thousand miles, capable of floating every 
article of commerce, the mighty river rolls its 
volume deep and placid to the ocean, as if it were 
absolutely supplicating the steam-ship in some 
such words as these — " Come, and bind into one 
brotherhood the various tribes of men which 
inhabit my banks. Come, and be the means of 
supplying all the world with the wonders of 
wealth which are watered by me and my tribu- 
tary streams." 

Much as has been done in the theoretical know- 
ledge and the practical application of these very 
general and most interesting matters, they may 
be said to be still in their infancy ; and every 
new step that is made only shows how much 
more of the bounty of the Creator remains behind 
for men to know and to do, and with how much 
more of the capacity both of knowing and of 
doing man has been endowed by this All-bene- 
ficent Being. 

At first sight, and especially when viewed in 
the common way of taking the details of a subject 
one by one, and then endeavouring to combine 
them so as to obtain a knowledge of the whole, 
the study of the earth appears a task almost 
hopeless ; for the lifetime of man seems altoge- 
ther too short for knowing all the plants on a 
single common, all the living creatures in a single 
lake, or all the birds in one forest ; and then, 
when to these w T e add the endless variety of 
mineral substances which present themselves to 
us in the varied species of earths and stones, of 
metals and their compounds, and of the fossil 
remains of animals and of plants, some of them 



fRELIMINxVRY REMARKS. 17 

analogous to existing species, and others of which 
no living individuals or almost types are to be 
found, the catalogue exceeds the bounds of imagi- 
nation itself, so that the most determined intellect 
might be turned away from it in the hopeless pain 
of its own feebleness. 

But there is another mode of viewing matters 
of this vast magnitude and endless diversity ; and 
in this other mode there is both hope and en- 
ticement. There is nothing of material nature, 
as it addresses itself to us, which the mind is not 
capable of mastering, provided we go the right 
way to work ; and in order to see which is the 
right way, let us take a particular case — that of 
the British metropolis. 

Suppose we had some wild man of the woods, 
who knew of no dwelling save the wigwam, the 
cave, or the hollow tree, for our pupil, and that 
we were to make him understand what London 
is like, how should we go about it ? Would we 
take the single houses, and describe in succession 
their materials, their structure, the arrangement 
of their several parts, and the advantage or dis- 
advantages of each mode ? Assuredly not. As 
little eould we hope to succeed by taking the 
details of all the streets and squares, and stating 
their several lengths, breadths, and directions, 
in terms of the length of the human foot, or of 
any other of those natural measures with which 
man in his most unlettered state is perfectly fa- 
miliar. Nor should we fare better if, instead 
of the mere still-life of the metropolis, we attempt- 
ed to detail to the woodsman the several nations, 
and ranks, and occupations of the vast multitudes 
wherewith this mighty city is thronged ; indeed, 



18 PRELIMINARY REMARKS. 

unless we could lay hold of some single, simple, 
and general feature of the city, which our pupil 
could in his own mind connect with what he 
already knew of men and their abodes in his 
own country, our labour would be in vain, and 
he would turn away from us, even though we 
addressed him in his own language, as if we 
were wasting his time in making him listen to 
sounds to which he could attach no meaning. 

In respect of all subjects of which we know 
nothing, we stand in nearly the same relation as 
the tenant of the woods would do to the city ; and, 
therefore, upon all subjects it becomes necessary 
that we should be presented with a first view, 
as clear and as simple, but at the same time as 
broad, as possible ; and when we have fully mas- 
tered this, and seen all its bearings, and how we 
connected it with what we previously knew, we 
are prepared for another step. After this is fully 
mastered, we may take a second, after that a 
third, and then, if we " walk warily," we can go 
as far, and in due time as fast, as we please. 

Still there are difficulties in getting a general 
view of the earth, which we do not meet with 
in any other subject. It presents us with so many 
elements; and these are so blended with each 
other in every thing, and every event which offers 
itself to our view, that we can hardly get hold 
of one element at once broad, strong, and secure 
enough for a foundation. Even if we leave out 
the influence of the sun, the moon, and other 
celestial bodies, upon the earth, there are three 
distinct subjects which demand our attention as 
substantive existences ; and there is scarcely one 
point to which we can address ourselves wherein 



PRELIMINARY REMARKS. 19 

all the three are not to some extent or other 
blended together. These are, the land, or solid 
part of our planet ; the water, or liquid part of 
it ; and the air, or portion of it which exists in 
the state of a dry fluid or gas. It is impossible 
fully to understand the nature and capabilities of 
the earth, or of any one portion, or any one pro- 
duction which it furnishes, without having some 
general notion of, at least, the great laws of action 
ki all the three ; but we purpose to treat of the 
water in one separate volume, under the general 
appellation of The Sea ; and of the gaseous 
portion in another separate volume, under the 
general appellation of The Air ; so that in this one 
we shall not explain any of the principles of either 
of these, though we may have occasion to refer 
to their distribution ; and, indeed, as the three 
are intimately connected, in any view which can 
be taken of the natural history of our planet, how- 
ever simple and elementary, we shall be obliged, 
in each of the three volumes, to assume as known, 
various matters contained in both of the others. 

Even when the subject is thus restricted, the 
story of the earth is a long as well as an interest- 
ing one ; and it involves several sciences, each of 
which treated singly affords materials for many 
and extensive works ; and all of those sciences 
may be said to involve two distinct parts — a pre- 
sent state, and a past or progressive history. 

It may not be amiss to enumerate a few of the 
leading sciences, the union of which constitutes 
the natural history of the earth, and to add some 
short definitions of them. The chief are the 
following : — 

1, Geography, which means the description 



20 PRELIMINARY REMARKS. 

or the representation of the earth, and which may 
be communicated in part by writing and in part 
by pictorial representation. The latter kinds of 
representations are called globes, when they are 
models or miniatures of the earth ; but in general 
the model applies to the general shape only, and 
not to the details, which are represented in the 
same manner on the globe, or model, as on the 
flat surface. Representations of the earth on flat 
surfaces are called maps, or, when their object is 
more particularly to represent the seas, or exten- 
sive collections of water, and only the shore of 
the land — that is, the lines where land and water 
meet — they are called charts. The word Geogra- 
phy, literally, means the description, or the arti- 
ficial representation, of the earth, and of course it 
applies to every means by which the earth, or 
any portion of its surface, can be represented. 

This single science of geography is so extensive 
that it requires sub-division into a number of 
branches. The leading one is Physical Geogra- 
phy, which treats of the earth in the most general 
sense, and not of its productions or inhabitants, 
though it embraces many of the causes upon 
which the diversities of these depend, whether 
these causes operate more particularly in the solid 
nature of the earth itself or through the instru- 
mentality of the water or the air, or both of these 
jointly. 

Natural Geography treats more particularly 
of the productions of the earth, the plants, and 
the animals ; but to their distribution upon the 
earth's surface rather than to the nature, liability, 
and uses of the individuals, or the classification 
of them into systems. The particular science 



PRELIMINARY REMARKS. 21 

which takes up the details of animated nature, 
where physical geography leaves off, is called 
Zoology, which means "the voice of life ;" and 
the science which, in like manner, takes up the 
subjects of the vegetable world is called Botany, 
which means simply " of or concerning grasses, 
or that which is browsed by domestic animals." 
Sometimes the latter science is called Phytology, 
which means " the voice of plants j" and as such 
it is more accurately descriptive of its subject 
than the word botany ; though as the latter has 
come into general use, the alteration would not 
be desirable. To these may be added the science 
of Mineralogy, which means " the voice of 
minerals" — that is, of those substances which are 
not either animal or vegetable, but which are 
constituent parts of the solid earth in the simplest 
view that we can take of it. The termination 
"logy," which is used in these names of sciences, 
is a very expressive one — it is from the Greek, 
logos — that which of itself declares itself ; and it 
always applies to the nature of the subjects, and 
in this respect stands distinguished from the ter- 
mination, "graphy," which means the mere 
description of the external appearance. 

Besides those divisions of geography which 
have been stated in the above paragraphs, and 
which form part of the natural history of the 
earth, considered as the subject of man's observa- 
tion, there are several sub-divisions which treat 
of man, the observer, in the various distinctions, 
and in the progressive history of the race. But 
though this branch of the subject may require to 
be noticed incidentally, in the course of these 
pages, it does not properly form part of the natu- 



22 PRELIMINARY REMARKS. 

ral history of the earth, considered as a separate 
subject of study. 

2. Geology, which means " the voice of the 
earth" — that is, the account which, taken as a 
whole, it is capable of rendering up to human in- 
vestigation, in its present state, its past history, 
and, as far as experience warrants the conjecture, 
its condition in future times. 

This, though it is one of the subjects to which 
the attention of mankind has been drawn ever 
since they had so far advanced in improvement 
as to be capable of speculating about the causes of 
things, yet the materials of our knowledge of this 
seience lie deep in the earth, and the events of 
which it affords the evidence lie in times so re- 
mote that it is very difficult to connect them with 
the present times, or even any times of which we 
have a human record. There is, however, a de- 
gree of grandeur in this science which renders it 
peculiarly attractive; and this grandeur comes 
more closely home to us than that of the heavenly 
bodies. In the deepest mine, under the summit 
of the loftiest mountain, which has been trod by 
human foot, there are traces of the universality 
of that wonderful working to which allusion has 
been made, and which, throughout the whole 
globe, and in every portion of it which we can 
by possibility examine, proclaims, in language 
not to be mistaken, that it is a production; and 
that, diversified as are its parts, and eventful as 
has been its history, it is the result of one creative 
fiat, and obedient to one law ; that all its changes, 
however mighty or however minute, and all its 
productions, however varied, are linked together 
in a most mysterious manner — a manner which 



PRELIMINARY REMARKS. 23 

leads the mind irresistibly to the belief of a Crea- 
tive Power and a Ruling Providence. 

3. Meteorology, or the doctrine of the air ; 
but, except in the case of an allusion, this will be 
referred to another volume. It is not possible, 
however, to give any account of the earth with- 
out making some allusions to the atmosphere, be- 
cause it is the medium in which all growth and 
life take place ; it being probable that there is no 
production, even of the deepest parts of the ocean, 
which can come into being or be supported with- 
out the agency of, at least, some portion of air, 
how small soever such portion may be in some 
cases. The same may also be said of water, and 
therefore it will be necessary to have frequent 
allusion to that liquid even in this volume. 

What have been stated are the general divi- 
sions of the substantive part of our globe ; but, in 
addition to them, there are what we may call the 
active powers of nature, and which we are never 
able to obtain separately, or bring to the ordinary 
test by which we judge of the presence of matter, 
— that of having gravitation or weight. Those 
active powers are so subtle that we can speak 
only of their effects, and are unable to tell any- 
thing about their natures, or how they agree or 
disagree, any farther than these effects make 
known to us. We are also ignorant as to the 
number of those active powers of nature, and 
whether those which we call by the same name 
are in all cases the same, or those which we call 
by different names are in all cases different ; but 
we cannot he wise beyond our powers of obser- 
vation, and therefore we must yield to our own 
weakness, and fairly confess that this part of the 



24 PRELIMINARY REMARKS. 

subject is, in its principles, altogether beyond our 
depth. Still the effects of those agencies are as 
open to our notice as the most familiar piece of 
matter upon which their effects can be displayed ; 
and when we attempt to get to first principles, 
even in the case of that matter which is palpable 
to the eye and the touch, we find that we can ex- 
plain nothing but the appearances, and that the 
general word matter is really as much beyond 
our comprehension as any of the others. 

Heat, light, electricity, and magnetism are the 
names which we give to those active powers 
which are understood to affect all matter, but to 
affect different kinds of matter in different ways; 
and the general effect of all of these may be said 
to be the counteracting of the gravitation of mat- 
ter, and the tendency of equalizing their own 
action ; but, at the same time, there are means of 
concentrating them in particular pieces of matter, 
so that the one portion may be made to act upon 
the other. In nature, there is probably no limit 
to the power of these agents — nothing in what 
we call substantive matter that can resist them. 
We all know the devouring effects of common 
fire ; we all feel the genial, and sometimes over- 
powering, heat of the sun-beams; and all of us 
may read of the terrible displays made by vol- 
canoes, and by, in all probability, the same agent, 
shaking the earth to pieces, and upheaving, from 
the bottom of the ocean, mountains and islands, 
which spread smoke and ashes over many miles 
of the sea — shoot up columns of flame, mingled 
with jets of boiling water, vast clouds of steam, 
and volleyed stone, hundreds of fathoms up in 
the air, while the waters around are boiling like 



PRELIMINARY REMARKS. 25 

a mighty cauldron, and the dead bodies of their 
finny inhabitants floating in countless numbers 
upon the surface. 

And we may read of vast pieces of molten 
stone bursting from the summit or side of a 
mountain, with seven-fold the heat of a furnace, 
and rolling onward for many miles, in a march 
of terrible devastation, so that, even when the 
stream does not appear in the day-light to be in a 
state of ignition, but advances like a wall of bricks, 
the strongest castles which man can build crumble 
into dust ere yet it reaches them, and every tree 
and every green thing is turned to the blaekness 
of ashes, while the powerful result of the opera- 
tion of heat is barely in view. Or, it may happen 
that this burning flood is more headlong and im- 
petuous, and converts in brief space a whole city 
into a ruin, but a ruin hidden from the view of 
man by that direful covering which, as it cools, 
hardens into one consolidated mass of rock, en- 
tombing alike frail man and the most boasted pro- 
ductions of his art ; or it may rain upon them 
mountains of ashes, by which, while yet in the air, 
it shall be as dark as midnight. And as, in such a 
case as this, there are no means of escape, for it 
must be instant suffocation, a splendid city may 
be thus blotted out from the world's history, and 
remain in its tomb of ashes during the lapse of 
centuries, to be again discovered by accident, and 
engage the attention of the curious, and claim the 
wonder of all mankind, as has been the case with 
Herculaneum, and some of the other buried cities 
of Italy. 

Such are some of the effects of the agent which 
we call heat, displayed upon the great and ter- 
3 



26 PRELIMINARY REMARKS. 

rific scale in nature ; and if we have positive evi- 
dence of these occurrences in several cases, and at 
several times, we have no reason to doubt that 
other cases, even far more terrific and far more 
extensive, have taken place, where there was none 
left, and probably none existed to tell the tale. 
And, though we have no human record of any 
result of the action of heat upon a more extensive 
scale than the overflowing of that district, the 
production of a mountain, or the raising of an 
island from the bottom of the sea, yet we have 
other evidence which is not less convincing, in 
vast tracts of country, which are now raised to a 
considerable elevation above the common level 
of the waters, which, from the countless number 
of shells, and other animal remains, which are in 
them, all clearly of a murrain character, must, at 
one period of the world's history, have not only 
been at the bottom of the sea, but must have been 
far, miles probably, in some instances, below the 
mean surface, and, from the thickness of the 
strata in which they are found, must have remained 
accumulating in that wonderful storehouse, the bot- 
tom of the deep, for a very long period of time. In 
the very centre of England, between the sources 
of those rivers which flow to the eastern sea on 
the one hand, and to the western on the other, we 
have countless remains of fishes, and deep sea- 
shells, and fragments of creatures, of various kinds, 
all of which must at some time or other have te- 
nanted the deep waters ; and there are other 
places where similar remains are found, at an 
elevation of two or three miles, and that too in 
immense ridges of mountains, in which it has not, 
at least hitherto, been discovered that there is a 



PRELIMINARY REMARKS. 27 

single trace of volcanic action at or near the sur- 
face. 

We shall have occasion to revert to these mat- 
ters when we have made a beginning of the main 
subject of our work ; and we have mentioned them 
now only to show that the earth itself not only 
has action in itself, as well as those productions 
and inhabitants of it of which we can see the pro- 
gress, but also that islands and continents, the 
most stupendous mountains, and the all-encircling 
sea, partake of that mortality which is the lot 
meted out by its Maker to every material thing. 
And, though we cannot number the years of a 
country with the same certainty as we can num- 
ber the days of its inhabitants, and consequently 
are unable to form a conjecture as to the number 
of centuries, or millions of centuries, which an 
entire globe may last, before the purpose of the 
Almighty concerning it is fulfilled, yet herein 
we see that the law is one, and that the differ- 
ences are all finite in extent, in power of endur- 
ance, and consequently in duration itself. Thus 
we can see the force of the sublime declaration of 
Holy Writ- — "The heavens shall pass away as a 
scroll when it is rolled together, and the elements 
shall melt with fervent heat." When this shall 
happen must remain unknown to us, because not 
a single ray of light comes to us from the depth 
at which it is hid, except the certainty that it 
shall come, the part which we must bear in it, 
and the means by which that part can be made 
joyful to us ; but still, in so far as we can judge 
of the state of our globe, it speaks as powerfully 
of the existence and the attributes of its Creator 
as if it were endowed with the tongues of angels. 



28 PRELIMINARY REMARKS. 

When we have said elsewhere, that those active 
powers of creation of which heat is one of the 
most general and the most energetic, either as a 
species or as a modification, we would not be un- 
derstood as meaning that it is confined to what 
we call dead matter ; for so far is this from being 
the case, that it is so intimately connected with 
that which we call the principle of life, both in 
animals and in vegetables, that there are just as 
good reasons for concluding that those principles, 
as we call them, are all modifications of some one 
energy — some one created energy, which is too 
mighty for our comprehension, and yet which is 
less than nothing in the sight of God. 

As, however, our object in the study of all the 
more mighty subjects in nature, and indeed of 
every subject upon which we would be truly 
wise, is to " divide and conquer," after we have 
got some general notion of what we are to divide, 
and how we are to conquer, we shall, in the sequel, 
consider the actions of those powers or principles 
in separate sections, yet still endeavouring so to 
blend the one with the other as not entirely to 
lose sight of that whole which is the subject of 
our general inquiry. 

But before we enter upon these, we must have 
some simple foundation — some tablet, as it were, 
upon which to record whatever may present itself 
to our view worthy of remembrance, either on 
its own account, or for the sake of the light which 
it may throw upon something else. For this 
purpose there is nothing better, and indeed no- 
thing else, than the common geographical des- 
cription of the surface of the earth, with the 
distribution of the land over it, which must include 



PRELIMINARY REMARKS. 29 

a slight notice of the positions of the several parts 
of the sea, as the boundary of the land. In ad- 
dition to this, it is requisite to notice the different 
appearances of characters of the different portions 
of the land, both with regard to geographical 
position, and seasonal and local influence. We 
must do this in a more broad and general style 
than is done in the common books of geography ; 
for we have the whole earth, as it were, before 
us at once, and therefore we must be in a condi- 
tion for making our mental journeys from one 
part of it to another in such brief space as that 
they may come into as close juxta-position as 
thought can follow thought. 

Nor is it with a view to studying the earth 
alone that this ready and accurate reference to 
the position and appearance of every spot of it is 
of great value to us ; for the map of the world — 
that is, the representation of the earth's surface — 
may be regarded as our artificial memory, or 
rather as the frame-work of our knowledge, every 
thing of which we have the means of informing 
ourselves. All that exists to astonish, to delight, 
to serve, and to teach us, as physical beings, exists 
on the earth ; and the different parts of the earth, 
even those which are the farthest asunder, and 
physically most different from each other, in their 
climates, in their productions, and their inhabi- 
tants, are still so beautifully adapted to each other, 
-that even here we see the unity of purpose, and 
how localities, as well as human beings, are evi- 
dently formed for being the helpmates of each 
other. In this there is wisdom, if we had but 
patience and prudence to work it out ; for if 
countries are kindred, it surely follows that their 
3* 






30 PRELIMINARY &EMA&KS. 

rational inhabitants ought to be brothers ; thai 
as land sympathizes with land, much more ought 
man to sympathize with man ; and that if y as we 
shall afterwards show, the thirsty sands of Africa 
and the great mountains in America work toge- 
ther so as to render our air in England much 
more balmy, and our fields to wave much more 
richly with corn than they otherwise would, then- 
ought we to make our fellow-men sharers with us' 
in the benefits of our science, and withal to bestow 
upon them the light of Divine Truth. 



31 



SECTION II. 

&EOGRAPHICAL REPRESENTATION, OR MAP, OF 
THE EARTH ? S SURFACE. 

In this case, we consider it best to introduce a 
slight notice of the representative map, before we 
speak of even the figure and magnitude of the 
represented earth, because the representation can 
be viewed as a whole and at one glance, whereas 
all of the real earth which can be seen at one 
view, under ordinary circumstances, is so exceed- 
ingly small a fraction of its surface, that it is cal- 
culated to afford no notion whatever of the whole. 
Direct personal observation is here necessarily a 
matter of mere detail, and of detail which we are 
unable to generalize without having recourse to 
celestial observation ; and hence the singular form 
which the ancients, and even the monkish delin- 
eators of the middle ages, gave to the map of the 
world. With the latter, it was very much a work 
of mere fancy; for the city of Jerusalem was 
placed in the centre, as if all the earth depended 
upon it. 

We mentioned that the earth is sometimes re- 
presented by the globe or model, and sometimes 
by the plain picture or map ; and, for all useful 
purposes, the map is beyond comparison the more 
serviceable of the two, not only in the details of 
geography, but more especially the studying the 
earth as a whole, in the relations of its different 
parts, and the results which we draw from the 
comparison of these with each other. The globe, 



32 GLOBE AND MAP. 

no doubt, gives mere beginners some notion of 
the figure of the earth ; and, if the picture upon 
its surface is correctly drawn, it shows all the 
countries, or portions of land, in their natural 
proportions to each other, or, as it is usually call- 
ed, upon the same scale. There are also various 
problems, relative to the situation of places on the 
earth, and the apparent motions of the sun and 
moon, which can be solved in a rude way by 
means of a globe ; but still these solutions are so 
very rude that, after all, the very best globe that 
can be made is little else than a mere toy ; and, 
as is the case with the most scientific toys, it is 
doubtful whether it may not, in some instances 
at least, do as much harm as good. The chief 
objections to it, however, are the unwieldiness 
and expense of a globe sufficiently large for ad- 
mitting of even a moderate representation of the 
details, and the fact that the larger the globe is, 
the less of its surface can be seen, at one view, at 
a readable distance. 

From these objections the map of the world is 
entirely free ; for we may represent the whole 
in one picture upon a pretty large scale, at a mo- 
derate price, and in a portable form, and we can 
have separate portions on a scale so large as to 
admit of very considerable minuteness in detail. 
The great advantage, however, with a view to 
studying the natural characters of the earth as a 
whole, is the fact that the two halves, or hemis- 
pheres, of the surface can be placed in two circu- 
lar portions, in close juxta-position with each 
other, and that thus the relative positions of all 
places may be seen at a glance. 

It is true that, as is the case with all human re- 



STEREOGRAPHIC PROJECTION. 33 

presentations of natural objects, whether by pic- 
tures or by words, the map of the world, or of 
any considerable portion of it, possesses some 
imperfections. This will readily appear when 
we call to mind that the representation and the 
represented surface are not surfaces of the same 
iind ; so that it is not possible to express the one 
in terms of the other. The map is on a plane or 
level, and is all turned one way, while the sur- 
face of the earth is turned every way, being di- 
rected at all times to all possible points in abso- 
lute space. As our object is not to teach either 
the principles of geography or the construction 
of maps, it will suffice for us to mention that there 
is a geometrical law according to which we can 
construct a map of the world, which, though on 
different scales in all places which are at different 
places from the centres of the circular spaces 
which represent the two hemispheres, but in 
-which all places equally distant from either of 
-those centres are upon exactly the same scale, 
and the variation throughout the whole of which 
can be calculated with perfect accuracy. 

The best form for this purpose is what is called 
the stereographic projection, which means the 
representation "drawn in the solid ;" and we may 
merely mention the principle upon which it is 
projected. Imagine, then, a transparent globe, 
.with all the features of the earth marked upon 
it, and that a circular plane, also transparent, is 
;placed within this globe so as to divide it exactly 
into two hemispheres. The particular direction 
of this plane is not an absolutely necessary con- 
dition to the accuracy of the map ; but the plane 
.of the earth's axis, or that passing through the 



34 HEMISPHERES, 

poles, and at right angles to the plane of the equa- 
tor, is the one which is most convenient for gene- 
ral purposes, and in this position of the plane the 
equator is represented by a straight line passing 
through the centres of both the circular spaces, 
or of both the hemispheres, as they are called. 
Neither is it absolutely necessary that the posi- 
tion of this plane should be fixed in respect of 
longitude, or of the direction of east and west ; 
but the most convenient is on the meridian of 20° 
west and 160° east of the meridian of London, 
because the only countries which are divided in 
this position are some unimportant portions of 
the north-east of Asia, the island of Iceland, and, 
probably, a portion of Greenland, which last is 
very imperfectly known, and not generally ap- 
proachable on account of the ice. 

These positions of the globe and the plane be- 
ing understood, the draftsman is supposed to place 
his eye in exactly such a situation as that the 
crossings of the equator and central meridian on 
both sides of the plane are exactly opposite to 
each other, and his eye quite close to the surface 
of the sphere. In this situation of things he is 
supposed to look at the opposite hemisphere, and 
trace upon the plane the figures of that hemis- 
phere, by passing a pencil or any other instru- 
ment that will make marks in all the places in 
which they appear to his eye. One hemisphere 
being traced in this manner, the draftsman is un- 
derstood to substitute a fresh plane, and look 
towards the other hemisphere from the centre of 
the surface of the first, tracing that other one in 
a manner exactly similar ; and thus the stereo- 
graphic projection of the two hemispheres is ob- 



THEIR POSITION. 35 

tained. It must be understood that the drafts- 
man traces his representation from behind each 
hemisphere, where to his view it is reversed; 
and that when it is represented upon the paper, 
or other plain surface which is to carry the map, 
it must be put in the opposite direction to that in 
which the draftsman sees it. The reason of this 
is very obvious, as anything viewed on the one 
side is reversed in respect of the view from the 
other; as for instance, if a building stands due 
east and west, the east end of it is towards one's 
right hand if viewing it from the south, but to- 
ward one's left hand if viewing it from the north. 

The two hemispheres are placed horizontally 
in the map of the world, and from one's left hand 
to one's right hand is from west to east in it, and 
from right to left is from east to west. Thus the 
hemisphere to one's right is the eastern hemis- 
phere, that to one's left the western hemisphere, 
the top is the north, with the north pole at the 
middle of the semicircle which bounds each, that 
is, at the terminations of the straight meridians. 
And the south and south pole are in like manner 
situated at the bottom of the map. The right- 
hand sides of places are thus their east sides, the 
left-hand sides are their west sides, their upper 
sides are north, and their under sides are south, 
and direction towards any of those boundaries is 
direction toward that point of the compass for 
which it stands. Only this must be received 
with some explanation, as it is perfectly true 
only in the case of the equator and the straight 
meridians. 

What we have now stated is the principle upon 
which the stereographic projection is formed ; but 



36 MERIDIANS AND PARALLELS. 

this principle is reduceable to the drawing of 
lines and circles, which, for the reason formerly 
stated, we are not called upon to explain. 

The surface of each of the two represented 
hemispheres is divided into a net-work by means 
of circular arches, meridians all meeting at the 
poles in each hemisphere, and parallels of latitude 
in the cross direction. The meridians have every 
degree of curvature from the straight line joining 
the poles to the semicircle bounding either side 
of the hemisphere ; and, therefore, the central 
meridian is shorter than any of the others, bear- 
ing to the bounding semicircle the proportion of 
about 100 to 157, or rather less than two to three. 
The meridians are drawn at every 10° of latitude, 
and the distances between them are in proportion 
to their lengths, and, of course, countries near the 
margin of the map are broader in proportion from 
east to west than those near the centre. The 
parallels of latitude are also drawn at every 10°, 
and they are so contrived as that the lengths of 
places from the centre toward the boundary, both 
northward and southward, increase in the same 
proportion as the breadths ; and thus the distor- 
tion which is inseparable from the expression of 
a hemisphere by means of a plane circular surface 
is the same both ways. 

There is another distortion to which we must 
attend, in order that our map may not give us 
erroneous notions of the positions of places with 
regard to each other, and the actual shapes which 
they have upon the globe itself; and this is the 
varying curvature of all the meridians, with the 
exception of the central ones; and the varying 
curvature of all the parallels, with the exception 



DETAILS OF THE MAP. 37 

of the equator. In consequence of this, coun- 
tries which lie near the margin of the map, or 
indeed at any considerable distance from the 
centre of either hemisphere, are bent toward the 
bounding circle in their north and south or lati- 
tudinal direction, and toward the centre of the 
map in their east and west or longitudinal one. 

The boundary circles on the margin of the map 
are usually divided into single degrees, and some- 
times into smaller parts, and the equator is di- 
vided in a similar manner ; and if the scale of the 
map be sufficiently large, it is easy, by dividing 
the compartments of the net work formed by the 
meridians and parallels by the eye, to find any 
place from its latitude and longitude, or con- 
versely the latitude and longitude of any place if 
the place itself is observed ; and in this manner 
the map readily becomes an easily consulted index 
to the geographical positions of all the details 
which are marked on it. 

The only means by which these details can be 
laid down in their proper places in the map is 
from their latitudes and longitudes, ascertained 
by celestial observation ; so that it is by means 
of the heavenly bodies that we are enabled to get 
a correct picture of the earth. As the latitudes 
and longitudes of only a few points, as compared 
with the wide surface of the earth, have been 
ascertained, there is much to be filled in without 
this accuracy ; but still the fixed points are the 
important ones, being those which are most re- 
markable for their natural properties, or most 
interesting to mankind ; and the vast number of 
travellers and observers who now visit all quarters 
of the globe, generally furnished with instruments 
4 



38 VALUE OF 

of observation and capable of using them, are 
making constant improvements in this part of the 
science; and for this reason it is desirable for 
every one who would know the details of the 
earth's surface accurately to procure a map of the 
newest construction possible. The date of the 
printing is, however, no sure guide in this matter, 
for the laying down of all the places correctly is 
not only very laborious, and consequently very 
costly, but it requires the combined qualities of a 
thorough knowledge of geography and of the 
means by which those latitudes and longitudes 
that are the data have been ascertained, together 
with a very judicious head and a very skilful 
hand. 

We have given this account of the map in pre- 
ference to giving a map itself j first, because no 
map which could be brought within the size of 
the volume, or sold for more than double the 
price, could be of much real use, more especially 
as he who would study the natural characters of 
the earth must have a map on which those cha- 
racters can be represented so as to give a mode- 
rately accurate idea of the general features of the 
surface ; and secondly, because a map inserted in 
a book cannot be constantly before the reader, 
but must be turned to when wanted, which is 
both a tedious and a clumsy mode of procedure. 
Unless the rivers, the mountains, and all those 
other prominent figures which are our means of 
judging of the earth, are marked with sufficient 
clearness and on a scale sufficiently large to enable 
the eye readily to make out their general forms, 
all the notions which the student can obtain of 
them are purely imaginary ; and as there is in 



A GOOD MAP. 39 

any case only one right, and innumerable wrongs, 
it requires no argument to show that they who 
fancy an earth to themselves for featureless 
miniatures, such as are generally inserted in 
elementary works of geography, and such indeed 
as can be afforded in these works, may have some 
crude notions of "a world of their own;" but in 
this case there must be as many different worlds 
as there are imaginers, and all of them unlike the 
reality. 

Such is the importance of studying intimately 
and correctly a good map of the world upon a 
scale as extensive as possible, that, independently 
altogether of the characters of the earth itself 
considered as a whole, no one is properly quali- 
fied for acting his part well in the common 
business of life, and no one is capable of duly 
appreciating the value of history, enjoying a book 
of travels, or in short of talking like a rational 
being about any of those countless foreign sub- 
stances which are now met with as the materials 
of articles of use or ornament, or as portions of 
food in almost every house within these king- 
doms ; and though we are not advocates for any 
morbid excess of legislation upon any of those 
points in the domestic conduct and economy of 
the people which do not trench in anywise upon 
morality, and orderly and becoming behaviour, yet 
it would be no bad rule to set the stigma of the 
neighbourhood upon every person who presumes 
to use anyone of these articles without being able 
to tell whence it comes, what are the general 
characteristics of its native country, how it is 
grown, or otherwise obtained, or how it is fetch- 



40 USES OF 

ed to this country, and what advantage there is 
in the using of it, whether as a means of innocent 
enjoyment or as a stimulus to our industry at 
home. 

If folks could once be led to this, it is incalcu- 
lable to conceive how much more delightful it 
would make the world we live in ; because it 
would enable us to live mentally, and in our 
mental life consists our real enjoyment in all the 
world at once. Thus, for instances, we should 
be enabled to drink our coffee in the groves of 
Yemen, with turbaned Arabs and loaded camels 
around us ; and under that balmy sky we could 
look athwart the Red Sea, which is there in one 
place an assemblage of worm-built reefs, extend- 
ing line upon line, and white with the foam pro- 
duced by an angry wind, and in another place 
reeking with the steam of volcanic fires, while 
the bottom is as gay as a garden with the vege- 
tation of the deep, and the waters are literally 
encumbered with living creatures. So might we 
drink our tea in some fantastic alcove in the 
pleasure-grounds of a Chinese mandarin, and 
enjoy the characters of that most singular coun- 
try, which has remained changeless for hundreds 
of years, amid all the vicissitudes, reverses, and 
progressions of our part of the world. We 
should never taste the stimulating flavour of 
cinnamon without being borne in thought to 
Ceylon, with its rich fields of rice, its beautiful 
copses which furnish this wholesome and exhi» 
lirating spiee,— its tangled and swampy woods, 
with their herds of gigantic elephants, — its more 
dry and inland lorests, peopled with countless 
thousands of apes, which make the early morn 



THE MAP. 41 

literally hideous with their cries, and the females 
of some of which may be occasionally found 
descending to the brook in order to wash the 
faces of their little ones ; so also we should never 
taste a clove or a nutmeg without being wafted 
to the spicy islands of the Oriental Archipelago, 
where all is the vigour of growth and beauty, and 
the richness of perfume, where perpetual health 
is wafted on the gentle gale of the widest ocean 
of the globe, where some of the fruits combine 
the qualities of the most racy of their own tribe 
with the substantial nourishment of delicate ani- 
mal food, and the admixture of a cooling ice and 
a cheering cordial, — while the trees around us 
would be thronged with the loveliest of birds, 
and the birds of Paradise, with their long and 
filmy feathers, streaming in every direction 
through the air, like meteors — meteors which 
shine but do not burn. 

But we must stop, for there is no end of the 
catalogue, and it is an exhibition of which we 
must not see too much at a passing glance, lest it 
should wile us from our proper purpose. And 
we have mentioned those few particulars merely 
to let those who are yet in ignorance of the sub- 
ject know how well the world is worth our 
studying ; how richly the earth which we inhabit 
has been endowed by its bountiful Maker ; how 
full the feast which it affords to all ; and yet how 
varied, how free from surfeiting, how healthful. 

Now, as we have already said, not only might, 
and should, every commodity of every region 
transport us to that region, and make it render 
up to our enjoyment all that it possesses ; but a 
map of the world, which has been duly studied, 
4* 



42 USES OF 

brings the whole before us the moment we glance 
at it, nor is it confined to the external appearance, 
and the productions, and the present population, 
of the several countries ; for in proportion to the 
extent of our knowledge will be the extent of 
the reminiscence which this most powerful talis- 
man will conjure up. Truly, it is magic, but it 
is magic of nature's exhibiting— the magic of the 
effect of infinite wisdom and goodness, without 
deception, without anything to mislead or corrupt, 
and with every thing to inform the head and 
soften the heart. 

As we look upon those two circular spots of 
paper, the whole of the human race, from Adam 
downward, rise in succession to our view ; and 
every event, pictured to itself, stands out as fresh 
and as forcible in its colours as if it were before 
our mortal eyes. Now we see the congregating 
clouds and the flashing lightnings, and hear the 
dismal sounds of the volleyed thunder, and the 
rending earth, as "the windows of heaven are 
opened, and the fountains of the great deep broken 
up," in order to drown the world, sunk in ini- 
quity beyond all mercy and forgiveness ; but in 
the very depth of the tempest terrors, behold the 
ark of deliverance, for the man who was faithful 
amid an offending race, riding safely on the top 
of the swelling waters ; and no sooner is the 
purpose accomplished, and execution done upon 
the guilty, than, lo ! "the bow of hope is seen in 
the cloud, and a promise of mercy is declared to 
a renovated world." 

Again we might call — or rather there would 
arise without our calling — any one scene in the 
world's history, whether sacred or profane. We 



THE MAP. 43 

might march through the divided waters with the 
delivered Israelites, and, standing safely on the 
shore, behold the overwhelming of Pharaoh and 
his host. So might we continue the stream of 
history down to the present hour, adding nation 
after nation as it arose, and losing it in the sandy 
desert of oblivion when it perished from the scroll ; 
and in tracing the sacred story we should be ena- 
bled, if we brought sufficient knowledge to the 
task, to ascertain, in a manner beyond all doubt, 
that the history of the Old Testament is so faith- 
ful to the natural character of the countries in 
which the scenes of it are laid, and so entirely 
free from all allusion to other countries, — so 
different, indeed, from every human record, in 
this respect, that it cannot but be true to the 
letter. 

It is the same with every art which mankind 
have practised, and every science which they have 
studied. If we once are in possession of the 
knowledge, and have had the map in juxtaposi- 
tion with us in the study of it, the map will not 
suffer us to forget it, but will faithfully bring to 
our recollection, at all times, every thing, of 
weal or of wo, that has happened to our kind ; 
and not to our kind only, but to all the creatures 
that now tenant the earth, or have formerly ten- 
anted it, in every one of its varied localities ; and 
the revolutions which the earth itself has under- 
gone, — either violently, by those convulsions 
that are now and then taking place, Or more slowly 
and silently, but with equal certajnty, in the lapse 
of ages, — may be equally brought to our recollec- 
tion by this invaluable record. The map will 



44 USES OF THE MAP. 

not furnish us with the knowledge at the first, 
but it will keep for us what we have acquired. 

In every case, indeed, we deceive ourselves, if 
we imagine that there is any short road to the 
acquiring of knowledge, — that is, of original 
knowledge, — while we ourselves are ignorant. 
If we know nothing, we can learn nothing. This 
may seem paradoxical, but it is a truth, and a 
very important truth ; for, before we can have a 
complete knowledge and understanding of any 
one subject whatever, we must previously have 
acquired that essential element of all knowledge, 
capacity, — the use, so to speak, of our own mind ; 
and we must not at all wonder that this should 
require general training, or educating, before we 
can apply it usefully to particular subjects. There 
is a general education of the hand, and also of the 
eye, and indeed of all the organs of the senses ; 
though in the case of these it takes place so early 
in life that we do not notice its progress. There 
is, however, no doubt of its existence ; and we 
can no more hope that the mind can intuitively 
know, than the hand can intuitively execute. 
Therefore, the truly valuable part of all education 
consists, not in teaching the knowledge of indi- 
vidual subjects, but in so disciplining the mind 
as to teach it how knowledge of all kinds may be 
acquired. 



45 



SECTION III. 

FORM, MAGNITUDE, AND GENERAL FEA- 
TURES OF THE EARTH. 

With the understanding that we have the map 
of the earth, as described, or rather noticed, in 
last section, spread out before us, — which will 
save much detail and repetition, and enable us to 
bring the different points more closely together, 
so as that they may better illustrate each other, — 
we shall proceed to notice the subjects enumerated 
in the title of this section. 

The earth, then, so far as we have been able to 
measure it, is a globular body, but not exactly a 
sphere, neither is it in all probability a perfect 
spheroid ; of which, even not taking the inequali- 
ties of mountain and valley into consideration, 
every section, on a parallel, would be a perfect 
circle. The deviations from the spheroid, and 
even from the sphere, are so small, that for com- 
mon geographical purposes they do not need to 
be taken into the account. But when we come 
to consider the natural history of the earth's mass, 
in so far as that mass can be the subject of con- 
sideration, these little irregularities are of im- 
portance, as connecting the form of the earth 
with the fact of its rotation on an axis, or imagi- 
nary line passing through the poles, and also with 
the fact of its being composed of materials, some 
of which are heavier and others lighter, and with 
that irregular distribution of those substances of 



46 FIGURE OF THE EARTH. 

different densities which we meet with in every 
part of it which is open to our inspection. 

Newton calculated that, according to the laws 
of gravitation and motion, and the rate at which 
the earth turns on its axis, it should have a 
compression, or flattening at the poles, of about 
one two-hundred-and-thirtieth part ; but then 
Newton's calculation was made upon the suppo- 
sition of uniform density, or that of all parts of 
the earth being equally heavy. Now, the best 
experiments which have been made on the sub- 
ject give to the general mass of the earth a density 
very considerably greater than the heaviest rocks 
which we meet with in any considerable quanti- 
ty near the surface. The mass of rocks, which 
form the greater part of the solid crust of the 
earth, so far as they iiave been examined, do not 
exceed two and a-half times the weight of the 
same bulk of water ; and as the metals, of which 
the quantity is comparatively small, at least near 
the surface, are the only substances heavier than 
this, we must suppose that, whatever they may 
be, there are materials in the interior of much 
greater density, because the average of the ex- 
periments which have been made, in order to 
ascertain the earth's density, gives a weight, bulk 
for bulk, about double that of the average rocks. 

There is every reason to conclude, from what 
has occurred, both in the surveys for the measur- 
ing of the earth and in the experiments which 
have been made with the pendulum, with a view 
to the ascertaining of how much it is flattened at 
the poles, that certain portions, even near the 
surface, are considerably more dense than others ; 
for there have been instances in the surveys, 



THE PENDULUM. 47 

where the plumb-line has been deflected much 
more than any difference of the surface level 
would appear to warrant, and these have disturbed 
the apparent, or rather perhaps the assumed, 
regularity of the compression, which, beginning 
at the equator, amounts to about thirty miles at 
the poles. So also in the case of the pendulum, 
which is probably a more nice and delicate instru- 
ment than the plumb-line and the apparatus of 
celestial observation, there have been irregulari- 
ties observed which show that our most careful 
endeavours to ascertain the exact form of our 
planet are still, to some extent, approximations ; 
and that, before we can speak dogmatically about 
how much it differs from an exact sphere, we must 
know something more about the data. 

The pendulum, such as that which regulates 
the motion of a common clock, — only for obser- 
vations of this kind it must be very delicately 
made, and furnished with apparatus which would 
be foreign to our purpose to describe, — returns 
from the extent of its swing on the one side by 
the force of gravitation, or the tendency which 
the bob, or weighty piece at the lower end of it, 
has to fall to the earth ; and the momentum, or 
accumulated force which it acquires from its re- 
turn on the one side, carries it to the extent of 
its swing on the other; but, however delicately it 
is constructed, it loses something of its power 
every time that it passes the line joining the 
centre of the earth's gravitation and the centre 
from which it is suspended, so that without an 
impelling power to counteract this influence of 
the earth, it would in time be brought to a state 
of rest. In the common clock, the weight or 



48 THE PENDULUM. 

spring which acts upon the train of machinery is 
the power which counterbalances the gravitation 
of the pendulum towards the earth, and keeps 
this part of the machine in motion ; and that there 
is considerable force exerted, is shown by the 
ticking of the clock, as the pallets attached to the 
pendulum and the teeth of the scapement wheel 
strike against each other. 

The more powerful that the force of gravitation 
is, the more strongly, and therefore the more 
quickly, must it draw down the bob of the pen- 
dulum towards the earth's centre ; and because 
the earth is flattened toward the poles, and eleva- 
ted round the equator, the poles are nearer the 
centre than the equatorial parts ; and, as the whole 
mass of the earth is the same, and the gravitation 
towards it, as depending on the mass, consequent- 
ly the same at every point of its surface, whether 
that point be nearer to the centre or more distant 
from it, the difference of gravitation at the equa- 
tor and the poles must be inversely as the squares 
of the distances of the surface at these places from 
the centre. Hence, reasoning from the form of 
the earth, we would conclude that the greater 
gravitation as we approach towards the poles 
would make a longer pendulum vibrate in the 
same time, than the diminished gravitation at 
the equator. Experiment shows this to be the 
fact ; and, indeed, it was from the circumstance 
of a pendulum adjusted to exact time, in the 
middle latitudes of Europe, making a clock go 
too slow when carried to a place near the equator, 
which gave the first practical proof of the ele- 
vation at the equator, and the flattening at the 
poles. The difference is no doubt exceedingly 



SOURCES OF ERROR. 49 

small, because the earth's deviation from a perfect 
globe is exceedingly small ; but still, though it is 
impossible to obtain extreme accuracy in experi- 
ments of so very nice a nature, yet the fact of 
a gradual flattening toward the poles is established. 
But we cannot expect that the particular form of 
the meridional curve, as determined by the pen- 
dulum, can be exactly the same as that determined 
by celestial observation. The pendulum gives 
the compression at the poles rather less than the 
other ; and it is probably nearer the truth, inas- 
much as it depends wholly upon the earth, and is 
not affected by refractions or parallaxes, which 
we have always to contend with in celestial ob- 
servation. Still, the two do not differ much 
from each other ; and it is satisfactory to find 
theoretical influence, as deduced from the motion 
of the earth, and two different modes of direct 
observation, all pointing to the same result. 

We have made these remarks on the uncertain- 
ties and sources of small error, against which it is 
impossible to guard in our attempts to determine 
exactly the form of our planet, in order to caution 
those who are but little conversant with such sub- 
jects and operations not to be carried away by 
confident assertions that such and such measures 
are the absolute truth. Indeed, when we come 
to real practice, there is no such thing as absolute 
truth, probably no such thing as a perfectly exact 
yard measure, and though there were one, no 
man could pretend to say that he could certainly 
make another exactly the same. We can measure 
just as exactly as we can observe ; and though we 
take a very small part, and have a very small 
error, — as for instance, if we were to take an 
5 



50 PENDULUM. 

inch and multiply it up till we came to miles, — 
we should multiply the error in the very same 
proportion as we multiplied the whole quantity, 
and thus not be more accurate than if we had 
saved ourselves the trouble of this excessive mi- 
nuteness. The principle which is here involved 
is well worthy of our attention, not merely in our 
attempts at the mensuration of the earth, or in 
any other mensuration whatever, but in all mat- 
ters : for, whenever we labour to be excessively 
i fine, we are either proportionally useless, or as 
much in error as in the ordinary way. 

There are one or two more facts connected 
with these pendulum experiments which may in 
time throw a little light upon the composition of 
the earth, at least in so far as the mere weight of 
materials is concerned. When the observations 
are made on islands situated in the deep sea, it is 
found that the pendulum indicates a greater 
degree of local gravitation than when experiments 
are made on the main land in the same latitudes ; 
and that if the islands are formed of compact 
volcanic matter, such as basalt,-— the rock which 
is so remarkable for the grandeur and regularity 
of its natural pillars at the Giant's Causeway in 
Ireland, the island of StafTa on the west of Scot- 
land, and many other places, — the local gravita- 
tion is greater than when the islands are formed 
of less compact materials. Now in the case of 
the island, it is specifically heavier than the water 
which surrounds it, and it is in mass the more so 
the deeper the water is ; and thus it, as it were, 
concentrates the local gravitation upon itself ; 
whereas, in an inland country, the said local 
gravitation is distributed all around, and there is 



EXPERIMENTS. 51 

in this distribution a tendency, though a very 
slight one, to retard the vibration of the pendulum. 

Upon nearly the same principle we may explain 
those local variations which have been observed 
upon the land, for they have been most conspicu- 
ous where it was ascertained that there existed 
some heavy stone in the vicinity ; as, for instance, 
a ridge of compact volcanic matter, a mass of 
granite, or something else specifically heavier 
than the general rock of the surrounding country. 

For all popular purposes, though it is desirable 
to understand the principles of those nice matters, 
we may leave them out of the estimate, and shall 
not err very much if we adhere to the round or 
simple numbers which are easily remembered^ 
and say that the earth is a globe 8,000 miles in 
diameter, or 4,000 miles radius, and about 25,000 
miles in circumference. These cost no trouble 
in the bearing in mind ; and when we require 
more minuteness, we can easily revert to the 
more complicated and fractional numbers, regard- 
ing the equator and a meridian as curves of 
different measures, and the first a circle but the 
other not. 

This being understood, we may return to our 
map, though there are one or two points of refer- 
ence in latitude which it is convenient to bear in 
mind. Latitude is definite measure on the earthy 
beginning at the circumference of the equator, 
and extending both ways to 90° at the poles. 
Thus there is something peculiar about it, inas- 
much as it begins anywhere on the circumference 
of a great circle, and terminates at points, which 
are the poles of that circle. The whole measure 
from equator to pole is rather large for reference, 



52 DISTRIBUTION. 

and therefore the division into zones is a conve- 
nient one ; the more so that it refers also to places 
which have certain peculiarities in the length of 
the day. 

From the equator to nearly 23^° both ways, 
forms what is called the torrid, the equatorial, or 
the inter-tropical zone, the last being its prefera- 
ble appellation, as it is described by its boundaries, 
the tropics, or latitudes beyond which the line 
joining the centres of the sun and earth never 
declines, either northward or southward. The 
latitude of these tropics is rather less than 23i°, 
but this is sufficiently near for the purposes of 
mere memory ; and it is sufficiently near also to 
consider the degree of latitude as containing 70 
British miles, though 69^ miles is nearer the 
truth. 

Beyond 66%° of latitude of both hemispheres 
— that is, a patch around each pole, about 23^° in 
radius, or 47° in whole breadth measured across 
the pole, — is called the polar zone ; and, in order 
to avoid the constant repetition of the words 
north and south as descriptive of the two poles, 
the north pole and every thing relating to it is 
called arctic, and the south pole and all relating 
to it antarctic. It is of some use to remember 
these names, because the star which at present 
and must for many years be considered the north 
pole star, is pointed out by being in a line with 
two very conspicuous stars in the constellation of 
the great bear (arctos.) 

The intermediate parts, extending from lati- 
tude 23^° to latitude 66§°, and each measuring 
43° in latitude, are called temperate zones, though 
it would probably be as well to give them a di£» 



OF ZONES. 53 

ferent name, insomuch as all parts of them are 
not temperate. 

We mention this division into zones partly 
because it gives us reference to larger masses 
than we can obtain by means of single latitudes, 
and partly because, from the common names of 
the zones, the ignorant are in some danger of 
being betrayed into error. When, for instance, 
one portion of the earth is called torrid, another 
temperate, and a third frigid, we are very apt 
to suppose that those names are descriptive of 
the qualities of the places to which they are ap- 
plied, and that there are no very hot countries 
except in the torrid zone, and no very cold coun- 
tries except in the frigid and polar ones. Now 
nothing can be more erroneous than such a con- 
clusion as this, for the boundaries of these 
zones are determined, not by the heat or cold of 
places, but by the position of the sun at certain 
times of the year. The heat or cold of any of 
them, or of any portion of it, does not therefore 
depend upon its being in a particular zone, or 
having a definite position in latitude, any further 
than the heat or cold of its climate is dependant 
on the sun ; and, under the same apparent enjoy- 
ment of solar influence, the circumstances of coun- 
tries differ so much, that this position alone is not 
sufficient for stamping the character of any coun- 
try. When therefore Ave refer to these zones, 
we are to be understood as referring only to mere 
position, and as leaving the characters of places 
to their own descriptions, though it be true that 
there is upon the average more solar action at 
the equator than on any other parallel, and that 
there is a gradual diminution as we recede from 



54 DIVISIONS OP 

the equator both ways ; the average climate being 
somewhere about the middle of the quadrant, or 
45° ; but that the poles are the points of greatest 
cold, instead of being demonstrated, is rendered 
doubtful by observations made on the north of 
America, where it appears that the very com- 
mencement of the polar zone, which is on a 
parallel with at least a habitable part of Europe, 
is colder than countries nearer the pole ; and if 
we take the middle of the quadrant, which gives 
us the south of France, in Europe, and trace it 
along to Canada, in North America, we find there 
the burning heat of fully a tropical summer, al- 
ternating with certainly not less than the rigour 
of a polar winter. We shall afterwards have 
occasion to examine the influence which the sun 
has upon the earth in different climates, as well 
as* those local or general causes by which this 
action is modified ; and therefore all that is essen- 
tial in the meantime is not to fall into error by 
supposing climate to depend wholly on the lengths 
of the day at different seasons, as measured by 
the apparent motion of the sun. 

With this understanding, when we turn our 
attention to the map, the first thing which strikes 
us is the remarkable way in which the two great 
constituent portions of the earth's surface, the 
land and the sea, are distributed. It is near 
enough, for the common purposes of memory, to 
assume that the entire surface of the earth contains 
about 200,000,000, of square miles. Of this, about 
three-tenth parts, or rather less than one-third, is 
occupied by land, and the remainder, being about 
seven-tenths, or more than two-thirds of the whole, 
is occupied by water. It being understood that 



the earth's surface. 55 

the term water is applied only to the seas and 
oceans, which are all connected with each other, 
and which consequently everywhere surround 
every portion of the land ; but that rivers and 
lakes are considered as part of the land, even 
though they happen to be salt water. This un- 
derstanding is necessary, because a river, and 
even a lake, really belongs to the economy of the 
land through which it flows, or in which it is 
situated, and not to the economy of the sea into 
which the waters of the rivers are discharged. 
Besides, all those mighty movements of the ocean 
which connect it, not only with the general econo- 
my of the globe of the earth, but with that of the 
solar system, are not found in those collections 
of water which we are considering as adjuncts of 
the land. When we look at the two hemi- 
spheres as divided by the circles which form the 
boundaries of the map, we perceive that there is 
considerably more land in the eastern one than 
in the western, and that in both there is far more 
land on the north side of the equator than on the 
south ; that the greatest breadth of land upon any 
parallel is somewhere near the fiftieth degree of 
north latitude ; and that the parallel of about 66h° 
falls upon the land throughout almost the whole 
of its length. 

In the opposite hemisphere, or on the south side 
of the equator, the land is not only much smaller 
in quantity, but it has a more tropical situation, 
and the different parts of it are farther apart from 
each other. Even here, they are not equally 
distributed ; for the Pacific Ocean, though stud- 
ded with islands in many places, will be found to 
occupy a full third of the circumference of every 



56 SOUTHERN LANDS. 

parallel in the southern hemisphere ; while, on the 
equator, the Atlantic occupies only about a sixth 
part, and the Indian Ocean rather less. But at 
the southern extremities of these oceans, as mea- 
sured from continent to continent, the distances 
are nearly the same. On examining the e:sfreme 
points of the land in each of those situations, and 
they are the most remarkable points on the sur- 
face of the globe, it will be found that Africa, 
which occupies the central position, extends to 
the latitude of about 35°, or we may say in round 
numbers 2,400 miles to the southward of the 
equator. Australia, taking to the southernmost 
extremity, the smaller island, Van Diemen's 
Land, reaches to about 44°, or we may say about 
3,000 miles ; while America extends to at least 
56°, and we shall not greatly err if we consider 
it as extending 4,000 miles south of the equator, 
which is about one-sixth part of the entire cir- 
cumference of the globe. 

It is true that Australia, which forms the right 
hand of the three great portions of land in the 
south, as we look upon the map of the world, 
does not extend to the equator, but is interrupted 
by Torre's Strait, in about 11° south latitude; 
but on the north of this continent, and all the 
way till we reach the main land of Asia, there 
are numbers of islands, which of course impede 
the motions of the water, and take the interme- 
diate narrow seas out of the general laws which 
regulate the wide oceans. New Guinea, the 
largest of those islands, has not been wholly 
discovered, but there is reason to believe that it 
extends within not more than half a degree of 
the equator without any interruptions except at 
Torre's Strait. This strait is also in general so 



NORTHERN LANDS. 57 

shallow that the bottom is visible, in calm and 
clear weather ; and it is full of islands, so that 
though the interruption between the Pacific and 
the Indian Ocean produced by the land is very 
much broken by channels, yet the land is suffi- 
cient to form a boundary to the general motion 
of the waters, and cause the Pacific on the one 
hand, and the Indian Ocean on the other, to as- 
sume different characters at the same time that 
there is an intercourse between them, not merely 
by vessels passing from the one to the other 
through the different straits, but by the reciprocal 
action of the two oceans upon each other, and 
upon the insulated portions of land. 

If we examine the hemisphere north of the 
equator, we find the state of things very different. 
Except the northern part of the Atlantic, the 
breadth of which is not very great, and Bhering's 
Strait, between Asia and America, which is narrow 
and not very deep, there is no communication 
northward between the oceans and the pole. It 
is known that for part of the year the ice of the 
Arctic Ocean joins land to land at both of these 
passages; and that it is probable that, in some 
seasons at least, there is no open water during 
any part of the year. 

The different circumstances in which the two 
poles or polar portions of our globe are thus situ- 
ated, must, it will readily be seen, impress upon 
them considerable differences of character; and 
it is necessary to attend to those differences, and 
to know their causes and also their effects, before 
we come to any conclusions respecting the coun- 
tries which are situated in them. 

From mere inspection of the map, it will at 
once be seen that there can be no great current 



58 NORTH OP ASIA 

of the waters of the oceans circulating in any way 
round a parallel on the north side of the equator, 
but that on the south side of the equator there 
may be such a current circulating with compara- 
tively little interruption as near the equator as 
the fortieth or fiftieth degree of latitude. There 
is no question that most of the differences of cha- 
racter which we meet with between places having 
the same latitude, on the north side of the equator 
and on the south, are owing to this absence of 
the means of a circulating current in the one, and 
presence of it in the other ; but we shall be better 
enabled to estimate the influence of this difference 
when we come to a future section, and are in 
possession of more of the elements. 

Let us next examine the form of the land in 
respect of its mere boundary ; and here we may 
as well mention a word which is very convenient 
when we attempt to describe the directions of 
the coasts of land, or the shores of seas. When 
we say that the position is in any particular di- 
rection, instead of saying that it extends, or lies, 
or stretches, or runs in that direction, we say it 
"trends ;" and if we keep this meaning of the 
word, it gives us a clearer notion than any of the 
common words by which we usually express either 
states of rest or kinds of motion. 

With this understanding we may begin our 
survey at the point where the western and eastern 
continents are nearest each other, because it is 
there that the distinction between them is most 
clearly seen. This point is Bhering's Strait, 
which is just about the northern polar circle, lati- 
tude 665 ; from this point, the north coast of 
Asia trends north-westward, and keeps generally 
above 70°, reaching 76° at some points; but 



AND EUROPE. 59 

when we come to the coast of Europe it is less ; 
and, so far as is known of the former, the outline 
is more irregular. In Lapland, again, we have 
the extreme of Europe, reaching beyond the se- 
ventieth degree ; and if we examine the map, it 
is worthy of being borne in mind, that the same 
meridian, namely, the twentieth east of Green- 
wich, passes through the northernmost part of 
Europe, and the southernmost of Africa. 

On this north coast of the eastern continent 
there are some islands amidst the snow and ice, 
the most remarkable of which is Nova Zembla, 
near the north-eastern angle of Europe ; and 
Spitzbergen, remarkable alike for its barren cliffs 
and the vast masses of ice which fall thence into 
the sea during the summer season, is situated 
directly north of the continent, and lies nearer to 
the north pole than any land which has been ex- 
amined ; for the northern extremity of it is be- 
yond the 80th degree of latitude, and, therefore, 
not much farther distant from the pole than the 
length of the island of Great Britain. 

As we glance round the boundaries, it will be 
of use to bear in mind the forms of their outlines, 
because some part of the characters of countries 
depend upon these ; as, for instance, if the outline 
is much broken, we may generally conclude that 
the surface of the country is rugged and unequal, 
and, if the outline is even, we may in general 
conclude that the surface of the country is flat. 
These are not of course invariable and unerring 
means of judgment, but they are worth recollect- 
ing, as the means of keeping the subject before 
us, and ultimately guiding us to the truth. 

There is one other point which is worthy of 
our remembrance; and that is, the relative 



60 NORTH OF ASIA 

lengths of our measures, the degree of latitude i 
and the degree of longitude. Except in so far as 
arises from the earth not being a perfect sphere, 
and for ordinary purposes it may be so regarded, 
the degrees of latitude are every where of the 
same length: but it is of course different with 
those of longitude, for the meridians which mark 
the degrees of longitude all meet each other at the 
poles, while two meridians, ten degrees different 
in longitude, may be reckoned about seven hun- 
dred miles apart at the equator. The law accord- 
ing to which they diminish is that of the cosines 
of the latitudes ; that is, the radii of the circles 
forming the different quadrants; and any one 
who examines the bounding circle in the map, 
and imagines straight lines to be substituted for 
the circular arches which mark the parallels, will 
at once see that these lines shorten very slowly 
near the equator, but very fast near the poles ; 
and thus will have some notion of the law of their 
diminution, even though not conversant with 
mathematics. We may mention that, at 60°, the 
diameter of the parallel circle, and consequently 
the circumference of it, and also the degree of 
longitude, which is the three-hundred-and-sixtieth 
part of the circumference of every parallel, is ex- 
actly half of what it is at the equator ; that is, it 
is about thirty-five miles. If we call the northern 
boundary of Asia and Europe the parallel of 70°, 
and that is not very wide of the truth, we have 
the degree of that parallel about twenty -three 
miles and a half; and as the extent in the paral- 
lel is from 20° east, eastward, to 170° west, which 
is 170°, we may say, that in round numbers this 
northern shore of Europe and Asia is, on the 
straight line, about 4000 miles in length. 



AND EUROPE, 61 

In studying the outline of a coast on the map, 
it is desirable to observe what rivers fall into the 
sea on that coast ; because the lengths and direc- 
tions of those rivers give us some data for ascer- 
taining the general slope of the country, and this 
is at least one important fact in its natural history. 
Now, if we look back at this north coast of Asia 
and Europe, we find that there are several very 
large rivers which discharge themselves into the 
Polar Sea — as, for instance, the Lena, by a num- 
ber of mouths, between 120° and 130° east longi- 
tude, the Yenissi, by one long estuary, in between 
80° and 90°, and the Obe, into an inland sea, or 
arm of the sea, in about 70° east longitude. We 
observe that these rivers, together with others of 
considerable magnitude, though inferior to these, 
all flow towards the Polar Sea, and that on the 
average they traverse the country from about the 
fiftieth to the seventieth degree north latitude, 
that is, about 1400 miles north and south, taking 
them on the straight line, while the curvatures 
of some of them must be nearly double. Some 
of these rivers, as the Lena, for instance, fall into 
the sea in very high latitudes — the Lena as much 
as between 72° and 73° — so that we may infer 
that the whole of the country, for about 1400 
miles in breadth from north to south, through 
which these rivers flow, not only inclines or 
slopes towards the north, but has its coast nearer 
the pole than any other country of the same ex- 
tent with which we are acquainted. Hence we 
might, without any other means of judgment, 
conclude that this must be a part of the world 
remarkable for the intense cold of its winters. 
And, as the sea which lies along this dreary coast 
6 



62 NORTH OF ASIA 

is cut off from much communication with the 
main body of the ocean, in consequence of the 
high latitude, the ice, and the narrowness of the 
entrance to it, we may readily suppose that what- 
ever of compensating effect there may be in the 
waters as circulating over the surface of the earth, 
it must be in a great measure lost to this country ; 
and we accordingly find that, while the cold is 
very severe during the winter, and the ice does 
not thaw upon the coast even in the heat of sum- 
mer, yet upon the plains in the interior the heat 
of summer is often very great, and burns up the 
vegetation. The general name of this country is 
Siberia, as may be seen by the map ; and it is a 
country, so to speak, which is given up to its own 
climate, and cut off from even natural intercourse, 
such intercourse as air and sea have, with the rest 
of the earth. 

In the eastern portion of the north of Europe, 
as far as the White Sea, that rivers of considerable 
magnitude, of which the Petchora and Dvina are 
the chief, flow toward the Arctic Ocean ; but 
though the winter is severe in the valleys of 
these rivers, especially in that of the Petchora, 
they are separated from Siberia by a ridge of 
mountains, and the mouth of the Dvina is in 
about latitude 65°, which is about 500 miles far- 
ther to the south than the mouth of the Lena. 
Still, the winter is very long and very severe in 
these countries, while the summer for a short time 
is often intolerably hot ; and this part of Europe 
may be said to partake much of the climate of 
Siberia, though it does not exhibit all the gloomy 
features of that land of winter, of desolation, and 
of ruin. 

In many places of this northernmost coast of 



AND EUROPE. 63 

the world, for in point of latitude it is the nor- 
thernmost which lies nearly on a parallel, we 
have something approaching a realization of the 
Ultima Thula of the ancients — that fabled 
country, which was neither land, sea, nor air. 
Some of the rivers flow over beds of ice even in 
the heat of summer, and in other places the soil 
or solid part of the country, such as it is, consists 
of a mixture of ice and gravel, which does not de- 
serve the name either of land or sea. On these 
extremes of the country there are of course no 
trees or shrubs ; and the only land animals are 
polar bears, which find their subsistence by the 
margins of the sea, and probably extend their 
expeditions in winter across the pole to the most 
northerly parts of America. But it is not a little 
singular that this land, which is at present a land 
of desolation, appears to have been at one time 
the habitation of animals of the largest growth ; 
for, even in the ice, where the rivers enter the 
-Frozen Sea, there are the bones of elephants and 
other large animals in vast numbers — numbers 
so vast, indeed, that they form entire islands; 
and near the shores, there have been found the 
entire bodies of animals of this class, preserved 
in masses of solid ice. So numerous are the 
remains of the elephant in this part of the world, 
that the tusks form a considerable article of 
commerce, although there has not been a living 
elephant in the whole country within the period 
of history. This is a singular point in the his- 
tory of the world. The fact that the entire ani- 
mal has been found preserved in the ice forbids 
us from supposing that at any period the climate 
could have been much warmer than it is at pre- 
sent; and yet, as all the larger animals have 



64 NORWAY. 

evidently perished, it has certainly undergone 
some strange revolution; and that revolution 
appears, from the traces of plants which are left 
in the deposites of soil, to have been as great in 
the vegetable kingdom as in the animal. 

After we pass the White Sea the character of 
the country begins to change ; and we find no 
more large rivers, or extensive countries sloping 
towards the north. Immediately between the 
White Sea and the Arctic Ocean, estimating di- 
rectly northward, there is indeed a low, swampy, 
cold, and inhospitable region ; but as we approach 
North Cape we find a bolder shore and a better 
climate, and this continues throughout the whole 
range of the west coast of Norway till we come 
to the Naze, or south point of that country, which 
is nearly opposite to the north point of the island 
of Great Britain. The coast here is bold and 
mountainous, very much intersected by arms of 
the sea, and studded with numerous islands, some 
of which are covered with natural forests, and 
some are inaccessible rocks. There are situations 
at which the currents of the sea flow between 
these with very great violence, and produce 
waterfalls and whirlpools of the most splendid 
character. In this part of Europe there is scarcely 
anything which can be called a river ; the waters 
having their sources at no very great distance 
from the sea, and flowing chiefly in brawling 
rivulets, which often dash down the rocks and 
through the forests with much grandeur. The 
number of small animals which the heat of sum- 
mer calls into existence in this country is very 
great; and the numbers of birds, especially of 
those which inhabit near the waters, that resort 
hither in summer for the purpose of building 



THE BALTIC. 65 

their nests and rearing their broods, is almost 
incredible to those who have not actually seen 
them. We shall, however, be better enabled to 
notice these matters at a future time. 

After the coast of Norway is passed we come 
to the entrance of the Baltic, an inland sea, which 
receives more than the average quantity of water 
from rivers, and from the entrance of which 
there is consequently a continual stream or cur- 
rent of water poured outward to the ocean. The 
Baltic, as may be seen by the map, divides into 
several arms or bays, the largest of which, the 
Gulf of Bothnia, extends northward in the direc- 
tion of North Cape, and the second in size, the 
Gulf of Finland, extends eastward to St. Peters- 
burg, the capital of Russia. The Gulf of Riga 
is further south than this, on the east side ; and 
there are some smaller gulfs on the south side of 
the sea. 

The greater part of the countries which are 
situated northward, or polarly, of the Baltic, have 
their principal slope towards this sea ; and, though 
the climate is not so warm here as it is upon the 
external or Norwegian shore, toward the open 
ocean, it is still by no means a cold climate for 
the latitude. Great part of the country is covered 
with luxurious forests of timber, the banks of the 
streams are very romantic ; and altogether it is a 
country of much interest, though decidedly polar 
in its character, and although for a considerable 
period of the year the sea is covered with ice, 
and the earth wrapt up in a mantle of ice and 
snow. 

On the south side of the Baltic the character of 
the country is entirely different; it consists in 
6* 



66 THE BALTIC. 

great part of accumulations of sand, or of light 
gravelly soil, with some patches of richer ground 
in the bottoms by the banks of the rivers ; and 
as many of these come from a considerable dis- 
tance up the country, they have in the course of 
time brought down vast deposites of sand and 
gravel, which form very singularly shaped bars 
near the mouths of some of them. Upon exam- 
ining the map it will be found that the principal 
rivers which empty themselves into the Baltic on 
this side are : the Neva, at St. Petersburg — which 
comes from two large lakes, Ladoga and Onega, 
which freeze in winter, are subject to violent 
storms, and send down such masses of ice that it 
becomes necessary to have moveable bridges at 
St. Petersburg; the Duna at Riga; the Niemen 
at Memel ; the Vistula at Dantzic ; and the Oder 
further to the west. Upon examining the last 
mentioned rivers it will be found that they have 
their sources considerably to the southward, and 
that there is in this part of Europe a large portion 
of country sloping towards the Baltic. These 
countries which slope toward the Baltic are not 
in so high a latitude as those which, in Siberia, 
the northern part of Asia, slope towards the Arctic 
Sea ; and they are protected from the polar blasts 
by the mountainous land on the opposite side of 
the Baltic. Still, as this country declines to the 
north, and is bordered by a sea which is generally 
covered with ice in whole or part in winter, and 
as the intervention of the high land in Sweden 
and Norway, and also the British islands farther 
to the south, cut it off from the action of the 
Atlantic, its climate runs more upon extremes of 
cold in winter and dry heat in summer than might 



WEST OF EUROPE. 67 

perhaps be expected from its latitude. As will 
be apparent from inspecting the straight outlines 
of this part of the Baltic, the shores are in gene- 
ral flat ; and in many places near the banks of 
the rivers, especially to the south-east of this sea, 
the surface is covered with forests of pine timber. 

From the entrance of the Baltic to the Strait 
of Dover, the coast is low and sandy, and the 
country flat, and in some places cold and barren. 
Some large rivers may be traced as entering the 
sea here, and determining the general slope of 
the country toward the north-west. The chief 
of these are the Elbe and the Rhine, the first 
coming from Bohemia, above the mountains in 
Germany, and the second from the centre of the 
Alps in Switzerland. Both these rivers bring 
down vast quantities of mud, so that the Elbe is 
very much interrupted by banks ; and the Rhine 
does not enter the sea as one river. Intermediate 
between these two there are smaller rivers, the 
Weser and the Ems, which flow through coun- 
tries which are well wooded and not very ele-* 
vated. 

From the Strait of Dover to the bottom of the 
Bay of Biscay, the coast will be observed opening 
to the English Channel and the Atlantic, and de- 
riving full advantage from the vicinity of that 
ocean. The general slope of the country is also 
to the west here, as may be seen by the courses 
of the Seine, the Loire, and the Garonne, in 
France. On the south side of the Bay of Biscay, 
the mountains in the north of Spain run very 
near the shore, so as to leave only a narrow strip 
of land ; and when we pass Cape Finisterre, 
which is about the westerly point of continental 



68 THE MEDITERRANEAN 

Europe, there are valleys in succession opening 
to the Atlantic, as is indicated by the courses of 
the rivers Douro, Tagus, Guadiana, and Guadal- 
quiver, in Portugal and Spain. The valleys of 
those rivers open to the Atlantic, and the southern 
ones especially have a more tropical character 
than any other part of Europe ; the rock of Gib- 
raltar, situated on the north side of the entrance 
to the Mediterranean, being the only part of the 
European continent where apes, of any species, 
are found in a wild state. 

The Mediterranean presents us with a singular 
feature in the structure of part of Europe and of 
Asia ; and the great valley, of which it forms the 
basin, extends from within ten degrees of the 
equator to the sixtieth degree of latitude, or nearly 
so : thus ranging over an extent of nearly 3500 
miles, from north to south, and carrying many of 
the characters of an ocean-surrounded country into 
the very heart of the continent. 

It is necessary to pay particular attention to the 
positions and relative magnitudes of the different 
parts and continuations of this important inland 
sea, because it has great influence upon the natu- 
ral features and history of a very extensive portion 
of the world ; which influence may be regarded 
as extending in latitude on the meridian from 
near the equator to the confines of the polar circle, 
and even within it. We may also join in the 
same central basin the great insulated salt lake, 
the Caspian Sea, — which is now on a lower level 
than the Mediterranean or its continuation, the 
Black Sea, and separated from the latter by the 
mountains of Caucasus, which are sufficiently 
elevated to have their summits covered with per- 
petual snow. To the northward of this moun- 



AND ITS BASIN. 69 

tainous ridge the country is flat, however, and 
abounds in marshes ; and there are pretty clear 
indications that not only were the Caspian Sea 
and the Mediterranean united at some period of 
their history, but that the water extended to a 
very considerable distance over what is now 
land, and was in all probability connected with 
the Baltic. 

On looking at the map, it will be seen that there 
is another large lake in central Asia, which may 
be regarded as belonging to the great system — « 
so to call it — of Mediterranean waters : this is the 
lake of Aral ; and it will be observed that two 
large rivers, one from the south-east, the Oxus, 
and another from the east, the Sihon, fall into 
the lake of Aral, and have their sources as far to 
the eastward as the seventieth degree of east lon- 
gitude. 

As the centre of this great basin may be con- 
sidered as lying on the parallel of forty, where 
the degree of longitude is about fifty-two and 
a-half miles ; and as it occupies, if we take it from 
the Strait of Gibraltar eastward, about 70°, on 
this parallel, its extreme dimensions in longitude 
cannot be estimated at less than 3600 miles ; or, 
if we average the western termination, the dimen- 
sions may be stated at 3500 miles both ways, 
which is a very large, as well as a very diversified 
portion of the earth. 

It is true that we cannot consider this as one 
uniform and continuous country to the full extent 
of its extreme dimensions ; for, if we take the 
valleys of the rivers, it lies something in form of 
a crab, with one claw extending up the Nile into 
Africa, and another eastward into central Asia, 
by the lake of Aral, and the rivers Oxus and 



70 MEDITERRANEAN 

Sihon. Great part of the valley of the Nile, too, 
is very narrow, and is really little more than a 
fertile streak seaming the desert, and wholly de- 
pendant on the river for its fertility. The eastern 
rivers are also separated from, the Mediterranean 
both by mountains and by deserts ; and the north- 
ern and western rivers have, in some instances, 
high mountains between them. But still there 
is a unity of character about the whole of this 
district, notwithstanding the ramifications and 
irregularities of its parts, and the vast difference 
of climate which it contains ; and this unity is 
felt in all its natural characters, and in its produc- 
tions, both vegetable and animal. It thus becomes 
important as a large portion of the earth, which 
has a common character, and a character which is 
more terrestrial than aquatic, that is, depends 
more on the land than on the sea. No doubt 
there is a great deal of water in the central parts 
of this region, but still this water is unconnected 
with the great oceans, or uninfluenced by their 
economy ; so that the influence which it produces 
is local, affecting only the land in its own neigh- 
bourhood, and being affected by that land and 
the rivers which it furnishes. 

This particular portion of the world is the 
grand historical portion, whether we regard it as 
connected with the history of man, of nature 
generally, or of any particular department of na- 
ture. It is the world, as known to the ancients, 
and it has the longest and the most varied story. 
There is also a progress of seasons, a succession 
of vegetables, and a migration of birds in this 
district, of all of which we require to inform our- 
selves ; and therefore it behoves us to get well 
acquainted with the local situations of the most 



BASIN. 71 

striking features, in order that we may convert 
them into a tablet of memory for the rest. 

All that is valuable of northern Africa may be 
said to belong to this valley ; but the mountains, 
beyond which the country gradually becomes 
dry, and passes into the great desert, are not far 
from the shore, and consequently the maritime 
country is reduced to rather a narrow slip along 
the coast ; and though there are numerous small 
streams, and also very productive fields in the 
states of Barbary, there is no river of any conse- 
quence on that side, except the Nile in Egypt. 

On the Levant, or eastern extremity of the 
Mediterranean, and also of its continuations, the 
mountains in general come near the shore, and 
the rivers are small. For more than the southern 
half of the Levant, which lies nearly on a meri- 
dian, the country is mountainous, and there is no 
river available for any purpose of communication ; 
but further to the north, the Orontes, though but 
a small river, passes within so short a distance of 
the Euphrates, that it points out a very obvious 
and easily effected communication between the 
Mediterranean water and the Indian Ocean, by 
means of the Euphrates and the Persian Gulf ; 
and it is worthy of remark, that at the present 
time there is a disposition, on the part of the 
rulers of that country, to suffer the establishment 
of a regular conveyance this way, either by means 
of canals or of railways, and of steam navigation 
upon the Euphrates. It is true, that the country 
is in a very unsettled state, and that the whole 
of the wastes are infested with predatory Arabs, 
who have never been honest at any period of the 
world's history ; but in former times, when the 
country was in a flourishing state, they were 



72 RIVEKS OF THE 

kept in subjection ; and there is no doubt that if 
a trade were once established, by means of which 
the country could be revived and renovated, they 
might be kept in subjection again. The wild 
men of the deserts live upon the weakness of na- 
tions ; and in proportion as the settled population 
waxes strong, they vanish. 

The peninsula of Asia Minor, which lies be- 
tween the Levant on the south, the Black Sea on 
the north, and the Archipelago, the Dardanelles, 
the Sea of Marmora, and the Strait of Constanti- 
nople on the west, is a mountainous country, 
containing but few rivers. It is, however, one 
of the most delightful climates in the world, and 
was at one time a great nursery of the arts. There 
are salt lakes, deserts, and other unpromising ele- 
ments in it ; but still there is enough of abundant 
promise to render it, in the hand of an active 
population, one of the most valuable countries in 
the world ; and it is worthy of remark, that the 
Armenians, who are natives of one part of this 
country, are the general traders over the east. 

We shall merely mention the rivers and valleys 
on the other side of the Mediterranean, and leave 
the reader to trace their positions in the map ; 
for this purpose we shall return to the western 
part, and just name the principal ones in their 
order. The plains of Murcia and Valentia, on 
south-east of Spain, are remarkable for their fer- 
tility, their beauty, and the richness of some of 
their productions ; but the rivers in them are 
short, as the central elevation is here near the 
eastern shore of the Peninsula, and the principal 
rivers flow towards the Atlantic. Farther to the 
northward, the Ebro, which drains the southern 
slopes of the ridge of the Py ranees, is a noble 



MEDITERRANEAN BASIN. 73 

stream, and its source lies considerably to the 
westward of the bottom of the Bay of Biscay. 

From the south of France we have the Rhone, 
a river of large size, the principal stream of which 
comes from the very centre of the Alps, and the 
northern one, the Saone, from the western side 
of the mountains of Jura, connecting all the south- 
east of France with the Mediterranean. To the 
eastward of the Rhone, the Alps and their south- 
ern spur, the Apennines, extend near to the 
shore ; so that, though the country on the margin 
of water is very beautiful, there is no river of any 
considerable magnitude. The chief streams of 
peninsular Italy flow to the Mediterranean ; but 
though they are renowned for their historic fame 
and the beauty of their scenery, they are upon too 
small a scale for being admitted as features in a 
general view of the earth. When we come to 
the other side of Italy, at the head of the Gulf of 
Venice or Adriatic Sea, we meet with a river 
and valley of more imposing character — the 
river Po, and valley of Lombardy. This river 
drains the southern slopes of the Alps, rolls a 
vast volume of water in proportion to its length, 
and presents some interesting features in natural 
history, to which we may have afterwards occa- 
sion to revert. On the opposite side of the Gulf 
of Venice, and round the whole shores of Greece 
and by Constantinople, till we come to the western 
side of the Black Sea, there is no river of much 
importance. The country is mountainous, or at 
all events diversified in its surface ; and most of 
the streams are torrents, flowing in deep channels, 
often with great rapidity, and corresponding 
beauty. 

7 



74 RIVERS OF THE 

When we come to the Danube, we may regard 
the district which it waters as the grand central 
valley of Europe ; for the river extends nearly 
two-thirds across the country, without reckoning 
its windings, and its tributaries come from the 
Alps on the one hand, and from the mountains 
which divide the waters toward the Baltic and 
the western sea on the other. This is the largest 
valley which opens into the Mediterranean waters. 

After we pass the mountains, or the height 
which may be regarded as the continuation of 
them, separating the valley of the Danube from 
the more northerly parts of Europe, we come to 
a country in which, the distinctions of mountain 
and valley are not so clearly made out ; and here 
we have some large rivers flowing southward from 
the centre of Russia, of which the Dneiper falling 
into the Black Sea, and the Don, falling into its 
continuation, the sea of Azof, are the chief. If, 
however, as the general character of the country 
requires, we admit the Caspian into this natural 
division of the earth, we have the Volga, the 
largest of European rivers, rising, by some of its 
branches as far north as about 61° latitude, and by 
others not far from St. Petersburg, and opening 
up a communication between the Baltic and the 
eastern seas. 

We omitted to mention that the river Nile, in 
Egypt, may be observed as being at no great dis- 
tance from the Red Sea, which is an arm of the 
Indian Ocean ; and that thus a communication can. 
readily be established between the Mediterranean 
and that ocean, by means of this channel ; but the 
Red Sea is rather a dangerous navigation. It is 
at certain seasons subject to most violent tempests; 



MEDITERRANEAN BASIN. 75 

and the reefs and shoals in it are constantly chang- 
ing their places. It has, however, been a line of 
communication between Egypt and India in most 
stages of the world ; and perhaps it is the earliest 
navigation of any extent which was carried on to 
such a distance. 

We shall afterwards have occasion to revert to 
the natural history of this highly interesting part 
of the earth ; and therefore we shall only further 
remark in the meantime, that as this central por- 
tion of Europe and Asia is cut off by mountains, 
or natural boundaries of some kind or other, from 
the action of the great oceans, so it serves to con- 
nect very great extremities of climate both in 
latitude and in longitude, and its natural history 
becomes in consequence equally varied, interest- 
ing, and instructive. Taking it to the extent 
which we have mentioned, its northern boundary 
is swampy forests of pine, or, farther to the east- 
ward, steppes or plains which are nearly destitute 
of vegetation, at least at certain seasons, and are 
at other seasons covered with pools of stagnant 
water, in many instances impregnated with salt. 
On its eastern boundary we have in succession 
the pine, the cedar, and the cypress, till we come 
to the acacia and the date palm in the southern 
climates ; on the west we have the pine, the larch, 
the oak, the beech, and other deciduous trees, ac- 
cording to the soil and the elevation ; and through 
them we gradually pass through the olive, the 
cork oak, and the orange, until we again reach 
the country of the date, which last may be said to 
be the ultimate tree on the margin of the African 
desert, by which the countries on the shores of 
the Mediterranean are cut off from the rest of 
Africa, farther to the south. 



76 EGYPT AND 

There are other changes which it is desirable 
to be acquainted with. At the western part of 
this great extent of country the climate and wea- 
ther partake, to some extent, of that habitual va- 
riableness without extremes of seasons, which we 
experience in our insular situation ; and as we 
proceed eastward, and approach nearer to Siberia, 
the weather is more regular to its seasons ; but the 
characters of those seasons are more extreme. 

The ridges of mountains and other interrup- 
tions, extending from east to west, break the con- 
tinuity over the greater part of the longitudinal 
stretch ; but there is one meridian which may be 
considered as affording an ample play to the whole 
northward and southward character of the region. 
This is nearly about longitude 32° east of London, 
or the situation of the Nile in the south, and be- 
tween the mouths of the Dneiper and Don on the 
North ; and here there is almost equal fertility in 
regions nearly 1500 miles apart in latitude, and 
less difference in the character of their produc- 
tions than we would be apt to suppose. The 
country which lies immediately to the north of 
the Black Sea is not indeed a country of palms, 
like that on the banks of the Nile ; but both are 
equally rich in grain and fruits ; both are enriched 
by the overflow of the rivers, and many of the 
fruits of both are exactly the same ; and, because 
of the rich soil deposited by the rivers, and the 
uninterrupted heat of the summer, they flourish 
better to the north of the Black Sea than in per- 
haps any other part of Europe. 

The most remarkable distinction between the 
rivers of southern Russia and the Nile, as affect* 
ing the general economy of nature on their banks, 



SOUTHERN RUSSIA. 77 

and in the intermediate regions, is the different 
times at which their overflows or inundations take 
place ; and as the causes of these are also of an 
opposite character, and tend to throw some light 
upon the connexion of tropical and polar influ- 
ence, we shall mention them, reserving the full 
explanation to our notice of the </lir, as that is the 
grand medium of intercourse between climate and 
climate on the earth's surface. 

The overflowing of the Nile is occasioned by 
the rains which fall seasonally in central Africa ; 
and in that part of the country whence the Nile 
is chiefly supplied with its water, the rains begin 
to fall in June, about the time when the sun is at 
its greatest apparent declination northward, or 
vertical at the northern tropic, or parallel of 23^°. 
The flooding of the Russian rivers is produced by 
the melting of the snows which have fallen in the 
central part of Russia in early winter, and which, 
as they lie on a flat surface, and melt very quickly 
when the thaw does set in, leave great part of the 
surface flooded with stagnant water, which creeps 
slowly to the rivers ; and, as their currents are 
also sluggish, they expand to the width of seas ; 
and the inhabitants of the villages, whose houses 
are erected on tall posts, have no intercourse with 
each other for some weeks, except by boats ; but 
no sooner is this inundation over, than the ground 
is covered with most luxurious vegetation, as if 
by magic, and the richness of the year far more 
than repays to the people the slight inconvenience 
to which they are subjected by the flood. 

By the time that this flood has partially sub- 
sided, and the joint action of the sun and moisture 
have begun to produce those swarms of insects 
7* 



78 MIGRATION 

and other small animals which are always met 
with at such places, the valley of the Nile has be- 
come parched, and all the products of the over- 
flowing of that river have been consumed. So 
the birds of innumerable races, wing their way to 
the northward, and find another Egypt on the 
banks of the rivers which flow into the Black 
Sea — the Danube, as well as the rivers farther to 
the north ; though the Lower Danube has itself 
the expanse of a moderate sea, and the islands 
with which it is studded are so numerous, and so 
tangled, that the winged multitudes which annu- 
ally visit it are perhaps not so conspicuous. It is 
not the water birds alone which partake in this 
great movement, for it applies equally to all birds 
which feed their young chiefly upon the larvae of 
insects and on worms, which are the common 
food of most young birds. In this country we 
have many feathered strangers in summer, which 
take their departure before the winter sets in ; 
but with us the numbers are very trifling com- 
pared with what they are in this great basin of 
the eastern continent. The flocks of them which 
are seen on their journeys are quite incredible; 
and that not merely of small birds, but of those 
of large size. An intelligent traveller mentions 
having stood on the top of Mount Carmel, and 
seen three flocks of storks passing over him, in 
high flight, on their journey from Egypt north- 
wards, each flight about half a mile in breadth, 
and the whole requiring three hours to pass the 
traveller. Now, if we allow only twenty miles 
an hour,— which is a slow rate for any bird on 
migratory flight, for it is astonishing how speedily 
even a large bird, moving apparently slow, clears 



OF BIRDS. 



79 



the horizon, — if we allow only this rate, it will 
give us a stream of storks sixty miles long and 
half a mile broad, which one would imagine might 
colonize half the rivers in the world ; and yet this 
was but one exhibition of one species of the count- 
less multitudes of birds which pass and repass an- 
nually between the extremities of the basin of the 
Mediterranean waters. 

This basin, if its natural history were fully 
worked out, would form ample materials for not 
one volume merely, but as many volumes as 
would fill a book-case of considerable dimensions. 
We cannot, of course, enter upon the details of it, 
though we may perhaps have occasion again to 
revert to it, in order to show how very replete it 
is with instruction of the most delightful kind ; 
and also how, when we are once in possession of 
a few of the general principles, we can bring 
those principles to bear upon the details so clearly 
that every fact is explained the instant it is ob- 
served ; and every instance, both of perception 
and reflection, brings knowledge. 

There is one other general point connected 
with this important central portion of the eastern 
continent which we may mention, though it is 
hardly necessary, in as much as it will not fail to 
impress itself upon every one who brings even a 
moderate degree of reflection to the examination 
of the map. Glancing back at the map, we find 
that in latitude it brings the regions of the equa- 
tor and of the poles into natural connexion with 
each other by means of this tie ; and that if we 
take the sources of the western rivers, the Po and 
the Danube for instance, and the sources of the 
eastern ones, the Oxus and the Sihon, we find that 



80 ACTION IN LONGITUDE. 

the Alps of Europe are brought into connexion 
with the central mountains of Asia; and the 
breezes of the Atlantic, — which reach the Alps ? 
and are mainly influential in regulating the great 
seasonal characters of the weather there, — are 
thus made to unite with the Monsoons of the 
Indian Ocean, which seasonally pour out their 
rains, and fling their burden of snows upon the 
lofty summits of the Himalaya. We have seen 
of how much consequence the reciprocal actions 
of the north and south are to nature ; and those of 
the east and west are not less so. But if they are 
thus useful to nature, because nature works in 
concert and without jealousy or war, is it not evi- 
dent that they would be equally serviceable to 
man, if all the inhabitants of this wide district 
could be made to work in concert, without hos- 
tility and without animosity. It is thus that we 
derive lessons of true wisdom when we catch 
glimpses of great principles in nature : — but we 
must leave these matters to the reflection of the 
reader, and proceed to another subject. 



81 



SECTION IV. 

GENERAL FEATURES OP THE EARTH. EASTERN 

CONTINENT CONTINUED. 

When we extend our survey of the eastern 
hemisphere beyond the strait of Gibraltar, or 
inlet to the Mediterranean waters, we speedily 
come to regions of characters entirely new. Here 
we must attend to the curvature of the meridians ; 
because, as the shore lies near the margin of the 
map, the meridian is almost a circle, while our 
proper conception of it ought to be that of a 
straight line. The first country we come to, ex- 
tending southward to about the 29th degree of 
latitude, has a good deal of the character of the 
warmer parts of Europe. This is the kingdom 
of Morocco, which is cut off from the rest of 
Africa by the mountains of Atlas. These are of 
sufficient height for having their summits covered 
with snow, and they, therefore, give rise to rivu- 
lets and streams. A spur of the same mountains, 
proceeding in a north-west direction, and termi- 
nating at Ceuta, on the south of the strait, cuts off 
Morocco from the Mediterranean, and leaves it 
wholly to the influence of the Atlantic on the 
one side, and the mountain ridge on the other. 
The climate of this part of Africa is therefore 
more the climate of an island than of part of a 
great continent; and though it is not quite equal 
to the climates of the adjacent islands, the Cana- 
ries and the Madeiras, which have, perhaps, the 
finest climate in the world, it is still a delightful, 



82 NORTHERN AFRICA, 

as well as a productive country, even in the hands 
of an indolent population. 

But when we pass this small maritime country, 
we arrive at the most singular region on the sur- 
face of the globe — a region which unquestionably 
acts a most important part in the economy of the 
earth's surface; but as it acts through the me- 
dium of the air, the principle of its action cannot 
be perfectly understood without some knowledge 
of that. This region may be stated as extending, 
upon the average, about 2000 miles, from east to 
west, and not less than 1000 from north to south ; 
so that it occupies nearly as much of the surface 
of the earth as the whole continent of Europe. 

This vast extent of country contains neither 
river nor mountain ; and we believe there is not 
on the surface, or for some depth below it, any- 
thing which can be called a rock, or even a large 
stone. It is true, that the surface is not perfectly 
flat, that there are patches where water stagnates, 
and that some of these are of sufficient magnitude 
to be inhabited, and to resemble islands, only 
they are far more inaccessible than if they were 
placed in the very centre of the largest ocean on 
the surface of the globe, because the surface of 
the surrounding sand is as oppressively hot as 
the surface of the sea is refreshingly cold, as no- 
thing but animal strength can be employed in 
crossing them, and as, when the winds are up, the 
sand forms at once the billow on the surface, and the 
shower in the air. Generally speaking, however, 
the broad parts of these deserts are tranquil, and 
the only difficulty experienced in crossing them 
arises from fatigue, or the want of provisions or 
of water, or from the predatory bands by which 



AND THE DESERT. 83 

they are infested; for it seems a pretty general jft 
law, that if a region which is naturally bad be at 
all habitable, mankind make it worse. 

There is no doubt that those vast accumulations 
of sand, wherever we may meet with them,— ■ 
whether on the shores of the sea, as in many 
parts, of the east coast especially, of our own 
country, or more inland, in places where we have 
no evidence that the sea has ever been, — are 
always to be considered as ruins, and ruins which 
have been produced in the slow progress of time, 
and not by any violence or convulsion of nature ; 
because the powers which act in those convul- 
sions act upon masses of matter, and not upon 
the smaller portions. The effect of the volcano 
is as often to consolidate matter into rocks and 
mountains as to break them to pieces ; and the 
earthquake not only never produces accumula- 
tions of sand, but would be comparatively silent 
and harmless if its action were confined to such 
accumulations. Even the lightning, which we 
may regard as the most mild and feeble display 
of those great powers which affect the solid parts 
of our globe, never reduces substances to powder: 
it breaks rocks into fragments, and sometimes, on 
the mountain tops, even in our own country, it 
ploughs up the mossy soil in trenches, as if an 
army had been going about to fortify a camp ; 
but it never reduces to powder; and when it 
strikes the sands, it often turns a tube several feet 
in length into a coarse glass; and those tubes, 
which are nothing more than the sand melted, 
have sometimes been called thunderbolts by the 
ignorant ; whereas the real thunderbolt, that which > 
strikes with whatever energy or effect it may 



84 FORMATION OF SAND. 

strike, is merely an action, not a thing,— a phe- 
nomenon of matter, and not matter itself. 

Even the sea, except on its shores, and proba- 
bly only where the water, the land, and the air all 
meet, has no power of turning any substance into 
sand ; and " the oozy bottom of the deep," which 
is the grand receptacle for all matters heavier 
than water, which we lose sight of upon land, is 
not a region of destruction. The sea assails the 
cliffs, but its action is too great for originally 
preparing the materials of a sand bank, though 
banks are sometimes shifted from place to place 
by its action ; and though we find that, on the 
beach where the tide beats with violence, the 
pebbles are smoothed and rounded, they are not 
reduced to sand. 

In fact, the only means which we are aware of 
whereby those sandy wastes, which we meet with 
in different parts of the world, and in none more 
than in this wide expanse of Sahara in Africa, are 
those which are put in operation, at the surface 
of the earth, by the common action of the wea- 
ther. In our own country, it is highly probable 
that the accumulations of sand, which we meet 
with on some of the shores, and even those which 
form extensive and thick strata of rock under- 
ground, may at one time have formed rocks of 
what are considered a more primary structure, in 
combination with the beds of clay, and the strata 
of clay-slate which we meet with in other places. 
In the long continued action of the weather, the 
alternate operations of wetting and drying, to 
say nothing of freezing and thawing, — the effects 
of which are still more powerful, — there is energy 
enough for the decomposition of the hardest rocks, 



PROGRESS OF RUIN. 85 

if those rocks are not protected by coverings of 
vegetable soil, which soil does not remain long if 
it ceases to be covered with living vegetables. 

This progress of destruction is no doubt a slow 
one, and it must depend upon particular circum- 
stances whether the result of the destruction of 
rock by this surface action shall or shall not be 
the production of a desert. If, as the decompo- 
sition goes on, the sand, which is chiefly the 
flinty or silicious matter, which, though broken 
into small crystals, is not so fine as to be washed 
down by water and form a paste, is removed, as 
fast as it is produced on the surface, by the wash- 
ing away of the clay, then, of course, the rock is 
removed altogether, and either a bed of clay is 
left in its place, or a new rock is exposed to the 
weather. This removal of the sand as it forms, 
requires, of course, powerful action of the weather 
— pelting rains and sweeping winds, and it re- 
quires, also, that the surface shall be sloping, and 
not level. Countries, of which the surfaces are 
irregular, formed of hill and dale, and near the 
sea, are those upon which the weather is most 
violent and variable, and therefore most likely to 
remove any sand which may be produced in the 
manner now stated ; and such countries are also 
those in which vegetation is most likely to resist 
both the decomposition of the rock and the for- 
mation of a desert. Such countries, too, are 
always furrowed over with watercourses; and 
though the streams which run in these commit 
devastation on their banks, and sometimes break 
through the natural dams of rock by which lakes 
are inclosed, and pour these in overwhelming floods 
down the watercourses, yet, in consequence of 
the very great havoc which they thus commit at 
8 



86 SAND BANKS. 

one place, they usually make compensation at 
another, by forming a new deposit; and not un- 
frequently, the sea refuses to receive the ruin of 
the land, throws it back again into a bar, and a 
receptacle is formed for the subsequent debris 
and rubbish which is brought down by the stream. 

There is no doubt that the fine clays in the 
south of England, of which porcelain and the 
finer kinds of pottery are made, had once formed 
part of granite rocks, the sandy portion of which 
has been removed by the action of the weather 
in the course of ages, and probably now forms 
part of the banks in the estuary of the Thames, 
or otherwise on the east side of the island. Nor 
is this mere conjecture, for we find insulated 
masses of granite, standing, like ruins, high 
above the present surface where they are situated, 
and bearing evident testimony that they are frag- 
ments of rocks which are now gone. 

Wherever there are beds of sand, or of sand- 
stone rock, we may always conclude that they 
have been formed by some such action as that 
which we are now describing ; and that, though 
the waters may have carried them to the places 
of their deposit, and eddies of the wind, and also 
of the water, may have rounded them into small 
hills, yet their original formation must always 
have been at the surface of the earth, exposed to 
the action of the air and the weather. 

And we can see the progress of this disinte- 
gration in some places of our own country. Ben 
Nevis, one of the highest of the Scottish moun- 
tains, if not the very highest, has the upper part 
composed of porphyry, a very hard rock, which 
we shall probably have to notice afterwards, and 
a considerable portion of the upper part of the 



DECOMPOSITION OP .MOUNTAINS. 87 

mountain is destitute of vegetation ; there is rarely 
a night, even in summer, when it does not freeze 
on the top ; and it is never long without showers, 
there being very often a rain cloud investing the 
upper part of the mountain, while the sun shines 
brightly on all the country around. This is ex- 
actly such an action as is calculated to destroy 
rock, and which, in rocks of some structures, 
would separate the sand from the other ingredi- 
ents ; but all the component parts of porphyry 
are in very small particles, and, therefore, the 
utmost that the weather can accomplish is to 
break this rock into angular fragments, similar to 
those which are used in road-making. And, 
along the upper slopes of the mountain, there lie 
beds of such fragments, which would be quite 
sufficient for repairing all the roads in a county ; 
and the number of these, the level to which they 
have descended, and the large masses which, hav- 
ing been undermined by the weather and thrown 
down, are scattered around the base of the moun- 
tain, clearly show that Ben Nevis is in a state of 
decay, and that it requires only length of time to 
reduce its lofty summit to the level of vegetation, 
or even to that of the surrounding country. 

The difference between any portion of a small 
island near the sea, where there are rains and the 
means of fertility, and that of a country like 
Sahara, which is inland, and in a hot climate, is 
of course very great ; but still, though the power 
of destruction maybe more energetic in Africa 
than in Britain, it is a power of exactly the same 
nature ; it is the only power by which we can 
suppose such a result brought about, and, there- 
fore, the study of it is of great use when we 
attempt to understand the natural history of the 



88 CREATION. 

earth ; for it will not do on this subject to rest 
satisfied with the simple fact, that an}' one ap- 
pearance that we meet with is, — our business is 
to ascertain how it is, and, if possible, why it is. 
This becomes evident when we bear in mind 
that every thing we meet with is, as has been 
said, & production — the result of some secondary 
operation — which secondary operation is a natu- 
ral cause, and therefore not only open to our in- 
quiry, but urging us to inquire. It is not enough 
for us to fold our hands in idleness, and content 
ourselves with saying that any one appearance, 
or thing, or place, is part of the creation of God ; 
for it would be presumption in us to pretend to 
have the slightest knowledge of the condition of 
worlds, or of any portion of worlds, as they came 
immediately from the hand of the Almighty. All 
created things address themselves to us by a long 
line of descent ; and though we can see the secon- 
dary mode of production, and can trace it back- 
ward as far as facts and philosophy will bear us 
out, yet we cannot, and we dare not, even specu- 
late about the primary step, where Almighty 
power willed the commencement of a world, or 
of a race of its inhabitants. 

In these more mighty changes which take 
place on the earth itself, we must not be disap- 
pointed though we are unable to bring the times 
within the brief record of our chronology ; neither 
must We feel any disappointment though revela- 
tion does not come to the aid of our reason on 
these subjects. The purpose of revelation is our 
own welfare as immortals, and as such it neither 
could benefit nor be benefited by any inquiry or 
any information respecting the phenomena of the 
materia] creation : and it would be inconsistent 



ANTIQUITY OF THE EARTH. 89 

with the general law which we find running 
through the whole of nature that there should be 
a spiritual discernment of material things. For 
the purposes of philosophy, God has given us, as 
men, and in our own natural endowment, all that 
is necessary for us : and if he had revealed the 
same kind of endowment, or the same result to 
which this endowment leads, it would have been 
superfluous, — which, in creation, is an impossi- 
bility, altogether inconsistent and absurd. 

Take an example : — An oak, when in the full 
maturity of its growth, and just before it begins 
to decay at the heart — by how much do we ascer- 
tain by mere observation that the bole of it thick- 
ens, or the branches extend, in the course of an 
entire season ? But this is a large portion of 
the duration of the oak, for we cannot date it at 
much more than two hundred or three hundred 
years. Therefore, — in order to have a parallel 
case, and to bring, as near as it is possible, our 
observation of the oak to a proportion with human 
observation of the earth, in point of time, — let us 
suppose that a huntsman rides past the oak at the 
full mettle of his steed, by how much shall his 
passing glance ascertain that it has grown during 
the moment that that glance is cast upon it ? This 
is the proper mode of speculating on the changes 
which the earth has undergone : and the chief 
difficulty and source of error and failure which 
we have in this most exciting study, is getting 
rid of our common notions of time. 

We may rest assured that the tale which Sahara 
has to tell is a very long one ; and that, though 
we have no reason to doubt that, at one period of 
the world's history, this extensive district was 
once as rich as it is now barren, and as lovely as 



90 ANTIQUITY OF 

it is now desolate, yet that time must have long 
gone by ; and it is instructive for us to find on 
the surface of the earth, and evidently produced by 
natural causes acting at the surface, an instance, 
and a very striking instance, of similar antiquity 
to that with which we meet in so many places 
when we dig into the substance. We know not 
what change the conversion of this district into 
a desert may have produced upon the powers by 
which it was so converted, but we have evidence 
now that the valley of the Nile is not remarkable 
for the decomposition of rocks. The edifices 
reared by the Egyptians of old, are probably 
among the most ancient in the world, and yet, 
unless in so far as human violence has ruined 
them, they remain entire, while buildings of 
similar materials, and not one-fourth the age, have 
in other places crumbled into shapeless heaps. 
When, however, we leave the valley of Egypt, 
and go to the hill tops, especially those near the 
Red Sea, which are still exposed to violent winds, 
and at least occasional rains, we discover the same 
incipient ruin which has been mentioned as cha- 
racterizing the upper slopes of Ben Nevis. The 
rocks are broken into fragments, and, generally 
speaking, the clayey part has been washed into 
the fissures, so that the rain, when it does fall, 
runs off, and so supplies no spring, and produces 
no fertility. 

If we take the Egyptian monuments, those hills 
which are covered with broken stone, and the 
sandy deserts, we get at least three points, or 
epochs, in the history of the desert : the Egyptian 
monuments must be vastly more modern than 
the commencement of ruin upon the mountains, 
and this commencement of ruin must be vastly 



THE AFRICAN DESERT, 91 

more modern than the similar commencement 
which we may presume to have once taken place 
in the deserts of shifting sand. That we have the 
shifting sand in some places alternating in the 
hollows with the crumbling hills, and in others 
with little patches of verdure, we might be pre- 
pared to expect ; for so long as the country is 
sufficiently diversified for occasioning some sur- 
face action, we may very readily suppose that the 
sand and the more compact materials will continue 
for a long time to be removed, gradually exposing 
a new surface of the hill to the powers of destruc- 
tion. It follows almost as a matter of course, 
that the finer particles, which are suspendable 
for a long time in water, and which may be ob- 
served always colouring the water in a clay pit, 
will first form a waterproof deposit in the hollow : 
and this may continue for a long time a pool, or 
even an oasis, or island in the desert, and may 
afterwards furnish wells by digging, after a mass 
of sand has been blown upon it and destroyed the 
surface. 

When once a desert has been formed to the 
same extent as it exists here, — and, indeed, as it 
may be partially traced, and sometimes is very 
conspicuous, along the whole of the lower ground 
which separates the central basin of the eastern 
continent from the countries which lie to the 
south and the east, — when once such a desert 
has been formed, it tends to spread itself, as though 
it were an ill-conditioned sore, upon the earth ; 
and it does this the more readily the more ex- 
tensive it is, and the warmer the climate in which 
it is situated. We may mention, without antici- 
pating, that one of the chief means by which the 
air is cooled is the converting the moisture into 



, 



92 THE DESERT EXTENDS. 

vapour, and that, generally speaking, this opera- 
tion is nearly in proportion to the heat. This is 
the reason why the margin of the waters and the 
shade of trees are so cool and refreshing in sultry 
weather ; by their cooling tendency the trees, to 
some extent, and the water, if it is extensive, 
probably to more, perform a part the very oppo- 
site of that which the desert performs — they cool 
the air over them, and it descends and comes 
outwards in all directions from them, often a de- 
lightful and refreshing breeze, which tends to 
spread fertility. 

The desert, on the other hand, when beaten 
upon by the heat of the sun, especially when that 
sun is nearly over head, as is the case on Sahara, 
is intensely hot ; in consequence of this heat the 
air over it is continually ascending, like the 
smoke of a furnace, and the air from all sides 
around moves inwards to supply its place : but 
the air which thus moves towards the desert 
becomes hotter as it approaches, and therefore, 
instead of letting fall in rain any part of the 
moisture with which it is already charged, it 
drains the moisture of the surrounding parts ; 
and, as it is not cooled when over the desert, it 
lets fall none of its moisture, but ascends into the 
upper regions of the air, and there spreads to a 
great distance, carrying the moisture along with 
it. In this way it is highly probable that the 
moisture which the desert thus drains from the 
dry and scanty vegetation on the desertward side 
of the mountains of Atlas may descend in snow 
upon the summits of those mountains, or in rain 
upon the countries between them and the sea. 

This progress can easily be understood to be 



ORIGIN OF THE DESERT. 93 

much more rapid than the original conversion of 
a fertile country into a desert, and hence we find 
that there is not a little of its progress which has 
taken place within the period of authentic and 
not very remote history. On both sides of the 
valley of the Nile, and on every part of the mar- 
gin of the desert, which has been examined with 
sufficient care, there have been found the most 
conclusive evidence of former fertility and popu- 
lation, and in many instances abundant population 
and a high state of the arts. These evidences 
are traceable along the whole line of the desert, 
both in Africa and where it extends into Asia ; 
and in the latter quarter of the world, we have 
whole provinces now entirely unproductive, and 
ruins of magnificent cities, well known to history, 
in the progress of being buried in the sand. 

What may have been the cause which convert- 
ed the first portion of the earth into a desert of 
sand we have not the means of ascertaining ; but 
there is some reason to believe that the tropical 
character of the year which belongs to all the 
southern hemisphere, with the exception of the 
smaller islands, which are either of volcanic 
origin or the production of coral insects, has 
probably some connexion with the extent of 
desert which lies between the countries which 
communicate with one another by the medium 
of the Mediterranean waters and those which have 
the tropical seasons. We are not yet in posses- 
sion of all the elements ; but we shall afterwards 
be able, perhaps, to show, with at least a consi- 
derable degree of probability, that the circulation 
of the air and the waters freely round the south- 
ern hemisphere in not a very high latitude, and 
the cutting off the influence of the cold of the 



94 THE WILD AND THE WILDERNESS. 

south pole from any connexion with the climate 
and economy of the middle latitudes, which is 
the result of this circulation, is at least one impor- 
tant element in determining why, in the one 
hemisphere, the seasons should be chiefly broken 
into dry and rainy, while in the other there is 
the regular succession of spring, summer, autumn, 
and winter. 

In some parts of India we have at least a vague 
sort of evidence of the manner in which a desert 
might be produced. The action of nature is so 
powerful in that country, that if man ceases to 
practise his arts of culture for even a very short 
time, the memorials of himself and his works are 
speedily obliterated. If the country is so situa- 
ted that the periodical rains can reach it, man and 
his memorials are blotted out by the power of 
vegetation ; and the bamboo jungle, rising to the 
height of sixty feet in a single year, and bristling 
with spines which are almost as formidable as the 
bayonets of armies, first conceal his dwelling, and 
then give up the remains of it to the leopard, the 
snake, and the bat. If, however, the rains do 
not reach the country, the change would be of a 
very different character : vegetation would soon 
cease, and in brief space large tracts of ere-while 
fertile ground would be turned into unproductive 
deserts. There are many of the higher districts 
of southern India upon which it would be alto- 
gether impossible to obtain crops, except by means 
of artificial watering, often from wells which 
require to be sunk to the depth of two hundred 
or three hundred feet ; and we have only to sup- 
pose a stop put to the labours of man in such a 
country in order to conceive how a desert might 
be begun in it, and this desert once begun would 



THE GREAT DESERT. 95 

extend very rapidly. Indeed, from the violence 
of elemental action, probably at a time when the 
rains of the Monsoons extended more completely 
over India than they do at present, there are 
evidences of a very remarkable decomposition of 
what has once been the uppermost rock in that 
country. 

To enter into all the details of evidence, either 
as to the original cause of the great desert itself, 
or as to the effects which it produces in the 
general economy of the earth, would, however, 
require more space than we are able to bestow 
upon it ; and the full understanding even of what 
is known would require the introduction of prin- 
ciples which do not, strictly speaking, come 
within the scope of this volume. We shall, 
therefore, only offer one or two further short 
remarks on this very singular region of the world, 
— a region which, though it is most extended and 
conspicuous in Africa, yet stretches the whole 
way from the extreme west of that continent to 
the confines of Siberia, interrupted only by 
mountain chains and the valleys of rivers, the 
last of which it is gradually invading. Indeed, 
it is easy to see how very soon even a large river 
might be obliterated by the desert ; because if the 
sand once reach the banks, and drift into the 
channel, the water will steal through underneath, 
and the process of obliteration will go on much 
more rapidly than those who have not thought of 
the subject are aware of. And, in those situations 
where the river flows in a sandy channel, and 
receives no addition to its waters, we have proofs 
in many places that the evaporation alone is suffi- 
cient to dry it up ; for in Arabia, Persia, and 
various other countries, the greater number of the 



96 WESTERN 

rivers which rise in the interior mountains, and 
flow for some distance over the plains, are lost in 
the sand or dried up by the heat of the sun 
acting upon its surface. 

There is a peculiar species of vegetation which, 
as we may so express it, contends with and resists 
the desert ; this consists chiefly of saline plants, 
but these in time increase the evil. Though their 
growth is exceedingly slow, and they keep their 
places for long periods of time, yet they at last 
give way : and, as they decompose, the salts 
which they contain are left on the surface. In 
the wet season, there is generally some rain upon 
the desert as far as vegetation extends, and this 
rain washes the saline water into the hollows, 
where it poisons the waters, or at all events 
renders them bitter, whether those waters remain 
in pools at the surface, or sink down into the 
sand and are procured by digging wells. 

About the seventeenth degree of north latitude, 
on the west coast of Africa, the desert terminates ; 
and it is probable that there extends across the 
continent at that parallel a belt of country about 
half the breadth of the desert, consisting of an 
alternation of mountains and fertile valleys. 
The interior of this part is only imperfectly 
known, but it should seem that from the mouth 
of the river Senegal to the Bight of Benin, in the 
Gulf of Guinea, there extends a district which 
differs very much in its characters from the de- 
sert to the north of the Senegal. Upon looking at 
the map, it will seem that the Senegal, which 
rises at a considerable distance southward of its 
confluence with the sea, has some of its branches 
more in a direction from east, and that there are 
mountains, or at all events hills, between the 



AFRICA. 97 

upper part of this river and the desert. Also, the 
river Niger may be traced from nearly the same 
source as the Senegal, but flowing in the oppo- 
site direction, having a much longer course, and 
ultimately discharging its waters into the Bight 
of Benin by a number of mouths. The lower 
part of the valley of this river is but imperfectly 
known, but it is ascertained that the river dischar- 
ges by its numerous mouths a vast quantity of 
water, and therefore it is probable that there are 
extensive branches falling into the river from 
mountains, and probably across plains to the 
eastward; and that these continue or may be 
traced from the opposite sides of the same heights 
which give rise to the different branches of the 
Nile. At all events, it is certain that the country 
— which is nearly bounded on the north and east 
by the Senegal and the Niger, and on the west 
and south by the sea, and which is of considerable 
dimensions, being about 1,500 miles from east to 
west, and half as much on the average from north 
to south — is as remarkable for its fertility as the 
country to the northward is for its barrenness. 
Generally speaking, the coast of this country — 
which is low and swampy, wooded down to the 
water's edge, and rank with aquatic vegetation in 
many places — is very unhealthy ; and as this is 
the part of the world with which the slave trade 
was so long carried on, there is but too much 
reason for the natives being hostile to European 
visitors, or at all events suspicious of them upon 
very slight grounds. For these reasons, we 
know but little of this country, farther than that 
it is exceedingly rich, and might be rendered 
exceedingly valuable ; and we know also that the 
seasons in it. are very extreme, that the heat is 
9 



98 SOUTHERN AFRICA. 

intolerable, and the rains, when they do come, 
come with the utmost violence. The seasonal 
action between the northern hemisphere and the 
south, and between the Atlantic on the south of 
this part of Africa and the land, is, as it were, cut 
off by the desert, and the whole concentrated 
upon this portion of the country. The conse- 
sequence is, that upon this portion there is exerted 
more than the average degree of seasonal action ; 
and the excessive fertility, and also the unhealthi- 
ness, are results of the violence of this action. 

From the bottom of the Gulf of Guinea to its 
southern termination, it will be observed that 
the west coast of Africa preserves its general un- 
broken character. The coast is known at points 
as far as the latitude 15° or 16° south, and in this 
part of the coast there is the mouth of at least one 
river of considerable magnitude ; and this river 
leads us to some conjectures as to the interior 
of the country here, of which there is very little 
certain knowledge. This river is the Zaire, or 
river of Congo, in about 7° south latitude, and in 
one respect it resembles the Nile in Egypt, — 
that is, its waters rise when there is no rain in 
the country on the coast. It does not overflow 
the country as the Nile overflows Egypt, for its 
current is rapid, and it runs in a deep channel, 
as the Nile does in many parts of Upper Egypt ; 
but there is a decided rising of the waters in the 
channel, and this rising is so gradual, and conti- 
nues so long, that it must come from a country, 
either where the rains are less violent than they 
are on the coast near the mouth of the river, or 
where these accumulate in the hollows, and swell 
the waters of temporary or permanent lakes, 
from which they are of course much more 



FLOODING BY RIVERS. 99 

gradually discharged than they are from the 
surface of the ground, especially when that ground 
is uneven. 

This is a circumstance worthy of attention, 
because it throws considerable light on at least 
one of the characters of countries. If a river fyfjjj£tytf< 
either passes through a lake of much extent, or a 
collects its different branches into such a lake, ity 
can never be so much swollen by floods, or do so 
much damage to the country by this means, as 
one which has not a regulating dam, which is the 
purpose that the lake answers. It is of little 
consequence whether the accumulation of water 
be in a lake which is never emptied out, or in 
one which is merely seasonal, if the breadth of 
surface upon which the water is retained is the 
same in both cases; and the larger that this is in 
proportion to the breadth of the channel, the 
flooding of the river must be the less violent and 
of the longer duration. There are instances of 
this in our own country which are very striking, 
and the effects of which on the lakeless rivers 
are often alarmingly destructive. The rivers on 
the east of Scotland, from the Tay to the Ness, 
pass through no lakes of any consequence, and 
upon the mountains in which they have their 
sources the autumnal rains sometimes fall with 
fearful violence, and the floods sweep away the 
crops, the houses, the very land itself, and in 
some instances the inhabitants. The Ness is a 
river of several times the size of the neighbour- 
ing Findhorn, and some of its feeders rise in 
grounds more elevated, and situated in climates 
much more rainy; but, a few years ago, when 
the Findhorn, and the smaller rivers to the east- 
ward of the Ness, were sweeping their banks 



100 SOUTHERN 

with a desolating flood, the Ness expanded in its 
ample lake, was flowing quietly along its six or 
seven miles to its confluence with the sea, without 
disturbing the place of a single pebble, any more 
than in the driest season of the year. 

It is not known what course the Zaire takes in. 
the interior, nor what is the character of the 
country there ; but the continent is still suffici- 
ently broad for preventing any reciprocating 
action between the Atlantic on the west, and the 
Indian Ocean on the east; but, from the absence 
of rivers of any consequence, it must have little 
rain, or great evaporation. From the mouth of 
the Niger round the African coast to the entrance 
of the Red Sea, indeed to the mouth of the Nile, 
which is a line of coast between 8,000 and 9,000 
miles, there is not so much water discharged into 
the sea by rivers as there is into the north and 
west of the Black Sea from the Danube to the 
Don, which is not more than 500 or 600 miles. 

Hence, though we do not know what may be 
the particular form and distribution of the land in 
Southern Africa, we know that its character must 
be dryness ; and the character of the coast for 
about 800 miles, from latitude 16° southward, 
furnishes us with some means of ascertaining 
what must be the general cast of the heights, and 
this will enable us to turn them to some account 
in understanding the general economy of nature 
in this very singular quarter of the world. Along 
the whole of this eight hundred miles of coast 
there is not, — at least during the dry Monsoon, 
when the wind of Southern Africa is generally 
south-east, and this coast can be approached with 
safety, — any fresh water to be met with. The 
coast consists of dry hills of sand or indurated clay, 



AFRICA. 101 

covered with a few hard and prickly plants, and 
presenting an aspect as dreary as possible. It is 
a curious fact, that this length of desert coast in 
Southern Africa should be almost exactly the 
same as that of the desert coast of Sahara in Nor- 
thern Africa. We are not to infer from this that 
there is the same correspondence between the 
deserts themselves, though there is certainly a 
considerable extent of desert in this part of 
Africa. 

As the interior of the country here is more 
imperfectly known than it is even in the north, 
we must take our notion of its general characters 
from the position of the principal rivers, and that 
of the heights, which will, in some measure, pre- 
pare us for the peculiarities of seasons afterwards 
to be noticed. At about 29° south latitude, to 
the northward of the British colony of the Cape, 
there flows into the Atlantic a river of consider- 
able magnitude, the Orange river, which runs 
westward nearly on the parallel for at least 300 
miles, while its branches, which are numerous in 
the upper country, both from the north and the 
south, perhaps exceed this length. The upper 
valley of this river is broad, thickly wooded in 
many places, and in others containing rich plains ; 
the lower valley is narrower, but it is also very 
thickly wooded, and contains vast numbers of the 
larger antelopes, of Cape buffaloes, and of various 
other animals. Along the south side of the val- 
ley of this river there are mountains which divide 
the coast or Cape country from the interior, unless 
by a long and laborious march ; those mountains 
are, in some places, not less than 10,000 feet in 
height, and they are often covered with snow in 
the cold seasons, by which means they probably 
9* 



102 EASTERN 

tend to render this valley of the Orange Riv T er 
more fertile than it otherwise would be, and also 
give it a different climate from that of the Cape. 
The northern side of the valley is understood to 
"crop out" into a desert, a certain portion of 
which has grass and bushes in the rainy season, 
and this is understood to be one of the seasonal 
resorts of the vast herds of swift antelopes which 
are migratory in Southern Africa. 

The position of the central height to the north- 
ward of this is not known, but it must trend to 
the westward, because about 11° to the northward 
of Orange River there is a considerable river, the 
Zambezi, which falls into the Indian Ocean ; and 
beyond this river it is probable that an elevation 
extends northward to the sources of the Nile. 
Thus, the two coasts of Southern Africa are 
separated from each other, and the economy of 
nature on the west side is regulated by the move- 
ments of the Atlantic, while that on the east side 
is regulated by the Indian Ocean, and may be 
said to extend in a connected chain by Arabia, 
Persia, and India, to the Himalaya Mountains 
and central Asia. 

Before we glance at the seasonal action, it may 
not be amiss to examine the outline of the Indian 
Ocean. Those of Africa and Arabia are nearly 
straight, and many places of both are dry and bar- 
ren. The Red Sea and the Persian Gulf are so nar- 
row at their entrances that they hardly break the 
continuity of this line, though they are both in- 
terested, as offering lines of communication with 
Western Europe, and especially with the Medi- 
terranean, which, if they were once fully esta- 
blished, might tend greatly to the improvement 
of the countries adjacent. We have already 



AFRICA. 103 

mentioned that the navigation of the Red Sea is 
difficult, and confined to certain seasons of the 
year, but still it opens up a ready communication 
with Arabia and all the east of Africa, and the 
commodities there are peculiar, some of them are 
valuable, and the country is capable of much im- 
provement. The mountains which traverse great 
part of the African continent, about the tenth 
degree of north latitude, are understood to be 
very rich in gold, and before the discovery of 
America, a good deal of that metal was, and 
even now is obtained, not probably by systematic 
mining, though some of the native Africans can 
reduce iron from the ore, and therefore it is not 
unreasonable to conclude that they might dig 
gold from the mine. At all events, gold-dust 
forms an article of commerce on both sides of the 
continent, and it is probable that, in former times, 
most of the gold, of which large quantities were 
obtained by trade in India — where there are no 
■gold mines, was got from Africa, by the Red Sea. 
The Persian Gulf is of still greater interest. 
The confluence of the Euphrates with that gulf 
is not above 800 miles from the Mediterranean, 
in a straight line, and near Aleppo the river ap- 
proaches within 150 of the Mediterranean. It is 
true that much of the country is now desert, but t 
it is equally true that this is owing, in many in- 
stances, to man's neglect ; and if Europe and 
Asia, or, more strictly speaking, the Mediterra- 
nean and the Indian Ocean, could be united by 
this line, the advantages to all the people dwell- 
ing around both would be very great. 

Persia, which lies along the north shore of the 
Arabian Sea, or western arm of the north part of 
the Indian Ocean, on the parallel of about 25° 









104 SOUTHERN 

north, presents a low and sandy shore ; and 
though there are hills of various elevations, there 
are not, if we take the line as extended parallel to 
the coast of Africa and Arabia, any mountains till 
we come to the great central chain of the Hindu 
Kosh and Himalaya, which are in about latitude 
35° at this point, or about 700 miles from the sea, 
though to the eastward their direction inclines to 
the south. Beyond the Hindu Kosh we have 
the south-eastern part of the central basin ; and 
behind the Himalaya, extending in the direction 
of north-east, we have a vast stretch of country 
— at least, between 2000 and 3000 miles, and 
more than 1000 in average breadth, which is 
hemmed in by mountains on all sides for the 
most part ; and thus may be said to have no con- 
nexion with any sea. This country is but im- 
perfectly known, though we have every reason 
to believe that it is dry, and in many parts com- 
pletely a desert, and destitute of all kinds of 
herbage. It is presumed that its general height 
above the level of the sea is considerable, not less, 
-perhaps, than two miles, which is more than 
twice the height of our highest mountain, and in 
many places considerably more than this. It is 
called the table land of Asia, that name being 
given to districts of country, the general level of 
which is high above that of the sea. It is not to 
be understood, that when we speak of a table 
land we mean a land of which the surface is flat 
like a table ; for all that we mean is, that the 
lowest parts of the land are at a considerable 
height above the mean level of the sea, without 
any regard to the mountains by which the sur- 
face of the table land may be broken. The bor- 
ders of this portion of Asia are very mountainous, 



ASIA. 105 

and the interior of it is, as we have said, little 
known; hut there are no rivers of any magni- 
tude which issue from sources far into the moun- 
tains; and though there may he on it a few 
streams, which terminate in lakes, it does not 
appear to contain an expanse of water of any 
consequence. No doubt the largest rivers of 
Asia, whether they flow to the Arctic Ocean, the 
Indian Ocean, or the Pacific, rise on the confines 
of this table land. But the ridges of mountains 
on its confines are generally double, with the 
river rising and flowing for some distance through 
the valley between them, parallel to the table 
land. These mountains sometimes have the ex- 
terior ridge not only the loftier of the two, but 
so lofty that it freezes continually on their sum- 
mits ; and thus no water in a state of vapour can 
reach the interior of the table land over such 
barriers. In consequence of this, the country 
must be very dry at all seasons ; and as there are 
some parts of Persia, on the south side of the 
mountains, where it does not often rain, — perhaps 
not once in a year or two, — we may presume 
that on this table land it rains less frequently, 
and that, therefore, it is easily heated, and as 
easily cooled. Those two qualities always go 
together, in so far as the solid earth is concerned ; 
though, in countries where the warm surface is 
deluged with rain, the cold is very much increas- 
ed by the evaporation, as any one may feel in 
passing along a newly-watered road, or street, on 
a very warm day. It is of importance to attend 
to the position of this table land, and of the lofty 
mountains which lie between it and Persia and 
India, because, as we shall see afterwards, it per- 
forms a very important part in the whole eco- 



106 ALTERNATING ACTION OP ASIA. 

nomy of the Indian Ocean, and on the countries 
both to the west and to the east, as far as the 
Cape of Good Hope on the one hand, and Aus- 
tralia on the other. Indeed, much of the surface 
of both these countries bears a considerable re- 
semblance to that of this table land, so far as all 
three are known. At the Cape there is a fertile 
plain along the sea coast; but, behind this, the 
ground rises in successive terraces, each more 
barren than the other, till it at last reaches the 
great Karoo, which, in the centre of the country, 
south of Orange River, and just at the foot of the 
mountains, extends about 300 miles in length, by 
80 in breadth, is totally uninhabited, and consists 
of hard clay, the surface of which is seldom 
moistened by a shower, though, on the lower 
terraces, and the steps, or elevations between 
them, rains frequently fall with so much violence 
that the soil is swept into the sea, and the chan- 
nels of the streams are worn to such a depth that, 
in the dry season, the water is not visible, and, 
in the greater number, there is none to be found. 
It is supposed that a good deal of the interior of 
the country, to the northward of Orange River, 
and also to the northward of the Zambezi, par- 
takes not a little of this character, so that we have 
upon the line of the western coast of the Indian 
Ocean two elevated deserts, in some measure 
answering to one another, only that on the north 
side of the equator is larger and in a higher lati- 
tude than that on the south ; still we shall after- 
wards see how the action of those deserts will 
alternate with the summer and winter, and impart 
that general character to the seasons in all the 
countries which lie between. 

If we take Australia, though there are some 



ASIA AND AUSTRALIA. 107 

fertile spots on it, and though the rains fall, in 
the south part especially, with equal violence as 
in Southern Africa, yet from all the evidence 
which has been obtained, by the examination of 
the greater part of the north-west coast, we may 
assume that much of the surface of Australia is 
dry and barren, though it may not be elevated 
above the rains, as is the case with great part of 
the African Karoo. This gives us, at the other 
corner of the Indian Ocean, on the same parallel 
with Southern Africa, and equalling in size the 
table land of Asia, another extent of country 
adapted for acting alternately with that table land 
at the different seasons ; but there are local causes 
which interrupt this action, and take the inter- 
mediate lands from under its influence. 

We must have other elements before we can 
explain this action in a satisfactory manner ; but 
still it is desirable that we should take along with 
us all those peculiarities of the earth which affect 
the result ; and therefore it is desirable to look 
back at the map, between the northern parts of 
the ocean and the mountains. Here we meet 
with India, having something of a three-cornered 
shape, and sending large rivers both to the Ara- 
bian Sea on the west side, and the Bay of Bengal 
on the east. The Indus, the principal river on 
the west, rises beyond the most elevated ridge of 
the Himalaya ; but after passing through a gorge, 
or opening in the mountains, it receives a number 
of large branches from the opposite side of the 
ridge, though some of them also have their sources 
on the other side. Indeed, it is not unusual for 
the largest rivers, which rise in ridges of moun- 
tains, to have their sources beyond the loftiest 
summits. For a considerable part of its course. 



10& SOUTH-EAST OF ASIA. 

the Indus receives no branch, and in the lapse of 
years it has washed down immense quantities of 
sand and mud. As the country immediately east 
of the mouth of the Indus is very flat, there is a 
desert, which extends upwards nearly as far as 
the first ridge of the mountains. This desert, in 
many places, presents nothing on the surface but 
sand and crumbling rocks, and no water is obtain- 
ed unless by digging to the depth of several 
hundred feet; and we need not add that on such 
a country it seldom rains. Further south, the 
west coast of India presents a bolder shore. The 
peninsula of Gujerat is hilly, and a little way to 
the south, the appearance of the coast is moun- 
tainous, while a considerable part of the interior 
is a table land, upon which it seldom rains; 
though the seasonal rains on the coast are often 
so violent, that the torrents which they form 
sweep trees, and rocks, and everything before 
them. In the country nearer the Indus, which 
we have mentioned as being desert, the very 
same monsoon which breaks in rain upon the 
western Ghauts — for such is the name of the 
mountains, or rather the passes on the shores of 
India — sweeps over without depositing a drop of 
water, and ultimately breaks on the mountains, 
the sides of which it deluges with rain, and floods 
the branches of the Indus, and also those of the 
Ganges, or main river, which traverses the great 
valley of Bengal, and ultimately enters the bay 
of the same name. 

In noticing the remaining portion of the east- 
ern continent, as it appears on the map, we may 
be more brief, because in it the great action 
which regulates the seasons and their productions 
is between the land and the Pacific, or those por- 



EAST OF ASIA. 109 

tions of it by which the shores are washed. 
Generally speaking, the islands to the south- 
eastward of Asia are remarkable for the fineness 
of their climates, and the richness of their vege- 
tation ; only such parts of them as are swampy 
are very unhealthy. They are, however, the 
gardens of the world, at least of the eastern 
hemisphere of it ; and some of them are very re- 
markable, — the Japan Isles, for instance, which 
lie in nearly the same average latitude as the 
Strait of Gibraltar, have a tropical character in 
the low grounds, and many of the plants have 
the singular property of growing equally well in //?; 
greathe at and in extreme cold. It is curious, 
though we are not aware that any inference can " 
be drawn from it, that on the east coast of New 
Holland, a little south of Sidney, almost exactly 
in the same latitude as the centre of the Japan 
Isles, and differing only ten degrees in longitude, 
there is a small district, the Illawarra district, the 
vegetation of which is much more tropical than 
that of the country for a great way to the north, 
and also a great deal more beautiful. But we 
must cast a hasty glance on the general features 
of the western hemisphere, namely the Ameri- 
can continent, and then proceed to other matters. 
Upon examining the map, it will not fail to be 
observed that there is a very remarkable physi- 
cal difference between Europe and the other large 
divisions of the eastern continent. Europe is of 
comparatively small size, very irregular in its 
figure, and much intersected by seas, so that the 
greater part of it may be regarded as consisting 
of coast country ; and the only exception is per- 
haps a portion of the centre of Russia, and from 
the flatness of this part, and the quantity of snow 
10 



110 THE EASTERN CONTINENT. 

which falls upon it, there is very little of it in a 
state of desert, even during the heat of the sum- 
mer ; though to the northward of the Black Sea 
there are, on the flats between the rivers, approxi- 
mations to this kind of country, there are no 
trees ; agriculture is not carried on, and the sur- 
face is either pastured by the cattle of wandering 
tribes, or by wild animals ; and this is the only 
part of Europe in which any species of antelope, 
the characteristic ruminating animal of the desert, 
is to be found. 

In Asia and in Africa the case is very different, 
and we are perhaps within the truth when we 
say that a full half of the surface of Asia has the 
desert character for at least some part of the year, 
and in Africa the proportion is perhaps greater. 
The comparison of those divisions of the eastern 
continent very strongly indicates the advantages 
which countries derve from the vicinity of the 
open sea, both in respect of mildness of climate 
and general fertility. 



• ' 



Ill 



SECTION V. 

GENERAL FEATURES OF THE EARTH. 
AMERICA. 

The relative proportions of land and water, 
and the position of the land with reference to the 
whole surface, in the western hemisphere, are 
very different from those in the eastern. If we 
lay a ruler or extend a line in any way across 
the hemisphere from 60° north latitude on the 
western boundary, to 60° south latitude on the 
eastern, we find that, with the exception of a 
very small portion of the southern extremity of 
the continent, a still smaller portion of Asia at 
the opposite extremity, and a few groups of 
islands spotted over the wide sea, the whole of 
the land lies on the north-east side of this line, 
and that the whole on the south-west side is sea. 
The land, too, has more the appearance of being 
one than the eastern land ; but it is still nearly 
intersected in the middle, so that two distinct 
portions offer themselves for our description ; 
North America, extends from the isthmus of 
Panama, which is in 9° north, and about 79° 
west, northward to the polar ice, and having the 
greatest breadth about the parallel of 50° north ; 
but it also includes Greenland, — which is only 
separated by straits, if separated at all, and those 
straits do not appear to be ever altogether clear 
of ice. Its greatest extent in longitude is about 
the parallel of 70°, where it extends from about 
25° to about 7>S°. The western boundary lies 



112 NORTH AMERICA. 

pretty nearly on a straight line, and is washed 
by the North Pacific ; the most remarkable de- 
viations are, the peninsula of California, between 
23° and 33°, and the point of Alaska, from which 
the group of the Aleutian Islands extend in a 
curve toward the coast of Siberia ; and, indeed, 
if we follow this direction, we find a succession 
of islands, by Japan and the Philippines, to New 
Guinea, and thence north-westward into the Bay 
of Bengal. There are some portions of the north 
coast which remain still to be explored. The 
western half of it lies on the average at about 70° 
north latitude ; but farther to the eastward, where 
it is so irregular as hardly to admit of description, 
some portions, either main land or islands, are 
situated farther to the northward than any portion 
of the eastern hemisphere except Spitzbergen; 
and as the southern shore of this very remote land 
is the part which has been seen, it may possibly 
extend to the pole itself ; and this may be one of 
the reasons why the cold is so much more severe 
in winter than in the corresponding latitudes of 
any part of the eastern continent. 

The eastern side of North America is very 
irregular, being broken by inland seas, and sea- 
like estuaries and lakes. Above latitude 60° there 
is Hudson's Strait, which leads to Hudson's Bay, 
an inland sea, which is, at least, double the size 
of the Baltic. Between latitude about 46° and 
52° there is the estuary of the St. Lawrence, 
which penetrates the country to a great extent ; 
and then there is the vast assemblage of fresh 
water, the American lakes, the largest of which, 
Lake Superior, contains probably as much water 
as all the fresh water lakes in the world, with the 
exception of those of America. To the south- 



NATURAL FEATURES. 113 

ward, where the continent narrows, there are 
successively the Gulf of Mexico and the Carib- 
bean Sea, the details of which may be seen on 
the map. 

In order to understand the natural features of 
North America, we must begin with the moun- 
tain ridges, or other central elevations, or water- 
sheds, from which the rivers flow to the opposite 
seas, and not with the rivers themselves ; because 
these are so numerous, and many of them so 
winding in their courses, that it is difficult to 
trace them. When we take these elevations as 
the basis, there are four natural divisions, exclu- 
sive of the narrow portion south of the Gulf of 
Mexico : first, that which is exposed to the Polar 
Ocean ; second, that which is exposed to the 
Pacific ; third, that which is exposed to the At- 
lantic ; and fourth, the great central valley lying 
between the two former, and being, for various 
reasons, the most important of the whole in refer- 
ence to the natural history of the earth. 

The southern boundary of the first, or polar 
division, may be traced from the north side of 
the entrance of the St. Lawrence, and the average 
of it is nearly the parallel of 50° ; that is, the lati- 
tude of the south side of England, and the middle 
of Germany. This boundary is rocky and hilly 
till we come near the lakes, and then it passes 
over swamps and flats till we arrive at the stony 
mountains in about longitude 1 14°. The circum- 
stance of so great' a breadth of Polar America 
passing into the southern country, without any 
intervening mountains to interrupt communica- 
tion by means of the air, enables this portion and 
the central portion to alternate with each other 
throughout the whole of their range, — the polar 
10* 



114 CENTRAL PART 

influence carrying winter into the south during 
one part of the year, and the tropical influence 
carrying summer into the north during the oppo- 
site part. As the alternation of those seasons is 
not interrupted by any cross ridge of mountain*, 
it is much greater at each extremity, and of course 
along the whole line between them, than in any 
other part of the world ; and this being the case, 
there is, in spring and autumn, more variation of 
weather, more disturbance of the atmosphere, 
and consequently more rain or snow, according 
to circumstances, than falls upon the same paral- 
lel of the eastern continent. The surface, too, 
even on the borders of the valley, does not rise 
into so lofty mountains as we meet with in most 
other countries ; and a very great proportion of 
this surface is still occupied by primeval forests, 
and much of the central parts by lakes and swamps. 
Hence there is a superabundance of moisture, 
and along with this a superabundance of vege- 
table action during the summer half of the year. 
Though the principle can be better explained 
after we have considered the properties of the 
air, yet we may mention that the great heat of 
summer, and the warm surface and abundant 
vegetation, are circumstances most favourable for 
loading the air with humidity, that is, with the 
elements of rain or snow. • » 

But the atmosphere of this district does not 
merely abound with the elements of rain and 
snow, for the very action by which the atmos- 
phere is loaded with moisture tends to precipi- 
tate that moisture to the earth upon much slighter 
changes than would be required for effecting the 
same purpose where there was less action. The 
precipitation of humidity either as rain or snow 



OF NORTH AMERICA. 115 

depends upon the contact with each other of strata 
of air of different temperatures moving in differ- 
ent directions ; and of course it depends upon the 
general temperature, whether the moisture which 
is thus condensed shall descend liquid or frozen. 
It is always, or at least generally, out of the 
warmer stratum or current of air that the rain 
cloud or snow cloud is formed, and the spring 
rains are produced by the resistance of the north- 
ward portion of the air, which condenses the 
moisture of the warmer current from the south ; 
while the autumnal and early winter rains 
are produced from an invasion, as it were, of the 
northern air, and the result of this is rain or snow, 
according to circumstances. 

It is not on the plains or in the extensive val- 
leys any where that the greatest quantity of rain 
falls ; because, from the comparative uniformity of 
the surface, the state of the atmosphere, except at 
the times of the seasonal changes, which are to a 
very considerable extent brought about by the fad- 
ing of vegetation from the surface of the earth in 
autumn, and its revival again in the spring, and 
which, therefore, have not the most powerful effect 
upon a country like the central valley of North 
America, clothed as many parts of itare,aswe have 
said, with primeval forests of great luxuriance. 
This is, in the American valley, rendered more 
conspicuous, that is, the seasons, unless at the 
turns, are more uniform than if there were not a 
free circulation between the regions of the equa- 
tor and those of the pole. Hence, in that coun- 
try, those atmospheric changes which are the 
cause of those abundant rains are thrown more 
toward the mountains than in most places o( the 
world. The mountains on the eastern side of 



116 STONY MOUNTAINS. 

the valley, which will be found generally to con- 
sist of two ridges from about latitude 35° to lati- 
tude 42° or 43°, and portions of which on refe- 
rence will be found entitled the Alleghany Moun- 
tains, the Cumberland Mountains, and various 
other names applicable to local portions, are not 
only of no very great elevation, but the action of 
nature on both sides of them is nearly the same ; 
and therefore they have not very much effect upon 
the physical and meteorological character of the 
central valley. On the opposite side of that 
valley it is different: the mountains there, though 
not lofty as compared with many ridges in other 
parts of the world, are yet sufficient, both in 
height and in breadth of country which they oc- 
cupy, to separate from each other the natural 
action of the countries to the east and the west, 
or rather wholly to cut them off from each other, 
and stamp upon them very different characters. 
These mountains to the westward of the valley 
are called the Stony Mountains, and the fact of 
their getting this name explains to us at least some 
of their characters, for it shows us that at some 
reasons the action of the weather upon them must 
be so violent as to tear away much of the soil 
and expose the rock. Accordingly, we find that 
these mountains, and the plains at their base, are 
more abundantly supplied with rivers than any 
part of the world which we have hitherto exam- 
ined; and those rivers are no stinted streams, but 
roll immense volumes of water onward to the 
main trunks. About 50° may be regarded as the 
summit level where the valley slopes, on the one 
hand south to the Mexican Gulf, and on the other 
northward to the Arctic seas. On the first of 
these slopes the grand central river is the Mis- 



MISSISSIPPI. 117 

sissippi ; this stream is not the longest, neither 
does it by any means roll along the largest vo- 
lume of water, but it preserves more constantly 
than any others the central line of the valley ; 
and, therefore, it serves well for fixing in one's 
recollection the general position of that valley. 
There is only one large branch from the east, or 
left-hand bank of the river, the Ohio, which is a 
beautiful winding river, with, generally speaking, 
a slow current, and flowing through a very fertile 
district; the Illinois above and the Tennessee 
below the Ohio, or rather forming a branch of it, 
are among the principal of the left bank branches. 
On the right, the Missouri is a river formed of 
an almost countless number of branches, and dis- 
charging a vast quantity of water. Both the 
main stream and the branches are very impetuous 
in some parts of their courses, and roll down 
great quantities of sand, gravel and mud. The 
Mississippi itself has not only formed an artificial 
channel, elevated above many parts of the sur- 
rounding country, but it is continually altering 
that channel, by destroying and forming portions 
of the banks and islands in the channel, rolling 
along vast numbers of uprooted trees, and often 
by its overflows converting large tracts of the 
country, beyond the elevated artificial banks, into 
swamps and stagnant waters, which, in the lower 
part of its course especially, are very redolent of 
all kinds of aquatic life; including among the 
rest, the alligator and the soft-shelled or ferocious 
tortoise, and which nourish a most exuberant vege- 
tation, but which are exceedingly unhealthy to 
the human race. 

The forests in this immense valley consist of 
various kinds of timber. On the north of the 



118 VALLEY OF THE MISSISSIPPI. 

Mississippi portion, toward the great lakes, the 
prevailing timber on the light and dry lands is 
pine, and on those of better quality there is a 
great variety of deciduous trees, oaks, walnuts, 
maples, and an endless variety of others, general- 
ly differing in their species from European trees 
of the same genera, and more rapid in their 
growth, and more gorgeous in their foliage, but 
for the most part inferior in the compactness and 
durability of their timber. There is one charac- 
ter of these deciduous forests of North America 
which renders them highly valuable in orna- 
mental plantations, and that is the richness and 
varied successions of the autumnal tints. Some 
of our native trees fade into various shades of 
brown and russet, and others pass into the " seared 
and yellow leaf," preparatory to shaking off their 
summer attire, and taking their winter's repose ; 
but the American trees display colours far more 
rich, and, along with every shade of brown and 
olive, there are the purest yellow, and the most 
intense crimson. Those beautiful colours are of 
longer duration also than the autumnal tints of 
our trees, and though the subject has not been in- 
vestigated in a scientific manner, there is no doubt 
that these autumnal changes of colour are in pro- 
portion to the variations of temperature at that 
season, while the largely developed leaves and 
their beautiful green in the summer are owing to 
the then tropical character of this most extensive 
and highly- interesting valley. As w T e proceed to 
the southward, those pyramidal and evergreen 
coniferous trees, which are usually called Ameri- 
can cedars, but which are in reality junipers, form, 
upon the swampy grounds, forests so thick, that 
not a single sunbeam can reach the surface of the 



VALLEY OF THE MIS5JS3IPPI, 119 

earth for many square miles; and when we come 
to the lower parts of the valley, we find that 
magnificent tree, the deciduous cypress {taxo- 
dium disticha), which, in the form of its long 
and pendent feathered leaves, the softness of their 
green, the rich cinnamon colour of the boles and 
branches, and the immense size to which it grows, 
is one of the most beautiful trees in the forest. 
They are also few vegetables which rival in 
beauty the different species of magnolias, espe- 
cially those with large tulip-like flowers of the 
most delicate whiteness, which come out early 
in the season, before the leaves, and which are as 
grateful to the smell as they are pleasing to the 
eve. It would, however, require many pages to 
trace even the mere outline of this region of ex- 
cessive fertility, — a region which, in the abun- 
dance of its productions, both animal and vegeta- 
ble, is equalled by few on the surface of the globe, 
Yet even this is, in some respects, a ruin ; and, 
abundant as it is in waters, exuberant in woods, 
and swarming with animals, — some of which, as 
for instance the American bison, are of great size, 
and found in herds to the number of many thou- 
sands, browsing together on the w r ide savannahs, 
— and astonishing as are the flocks of birds which 
seasonally throng to the woods, thick as locusts, 
and absolutely built upon the branches, bird over 
bird, till the whole forests creaks and crashes un- 
der their weight, and countless thousands are pre- 
cipitated to the ground, so that the people resort 
thither to give their pigs an annual feast of 
pigeons ; — yet, notwithstanding all this, even the 
great valley of the Mississippi is, in some re- 
spects, a ruin ; for there are found, in various 
places of it, the bones and other remains of larg& 



* Hk 



120 THE MISSISSIPPI. 

animals of which no living specimen has been 
met with. Among these may be enumerated the 
same elephant of times long gone by of whose 
entire carcase a specimen was found preserved in 
the Siberian ice, and which clearly demonstrated 
that this animal had been of a polar or cold cli- 
mate character, and not the same with the living 
elephant either of Africa or of Asia. One thing, 
however, is singular: that the remains of the 
mastodon, — an animal which had rivalled the 
elephant in size, and agreed with it in its general 
haunts and more general characters, though dif- 
ferent in many of the details of its structure, — 
are found buried along with those of the elephant 
in the valley of the Ohio ; and that they occur 
also in South America, in France, in Germany, 
and in Siberia. Of the subjects, which press 
themselves upon one's attention while looking 
upon the map of this land of many waters, there 
is, however, literally, no end. 

If we take the central valley of North America 
from the average shore of the Polar Sea, which is 
here exceedingly irregular in its outline, to the 
Gulf of Mexico, we find that the central eleva- 
tion, or summit level where the water divides, 
lies about midway between them, being in central 
America about the parallel of 50°. This northern 
part has not, however, that unity which belongs 
to the valley of the Mississippi, but may be re- 
garded as divided into three natural parts, — the 
valley of the St. Lawrence, including the great 
lakes in the upper part, and not extending far to 
the westward of Lake Superior, the principal one, 
the division being about 94° or 95° west longi- 
tude. This valley hardly deserves the name in 
the upper part, or all the way above the great fall 



THE ST. LAWRENCE. 121 

of Niagara between Lake Erie and Lake Ontario, 
for the summit levels, or places of water-shed, m 
that part of the world are marshes, and not moun- 
tains ; and at those falls there is a breast work of 
rock, into which the river has cut a channel of 
more than six miles in length ; and if we are to 
suppose that the action of the water has been uni- 
form, namely, six or seven inches in the year, as 
it is at present, the time passed in the performing 
of this operation would amount to about two and 
fifty thousand years, The volume of water which 
works here is perfectly astonishing, being not less 
than six hundred thousand tons descending in the 
minute; and from the height through which it 
descends, the actual power which this falling 
water possesses, if it could be rendered available 
to the purposes of human art, would be equal to 
that of about a million of steam engines ! 

The elevation of the breast work of rock which 
here crosses the general valley of the St. Law- 
rence is about three hundred feet, though the hills 
which diversify it rise a good deal higher. Of 
this height, the fall occupies about one hundred 
and fifty feet, the great or Canadian fall being 
about one hundred and forty, and the American, 
eastern, or smaller fall about one hundred and 
sixty. The grandeur of this fall, whether we 
consider the immense power of the rolling water 
or the splendour of the scenery, is altogether 
beyond description ; and for this reason many 
circumstances respecting it have been greatly ex- 
aggerated, as is always the case when men attempt 
to describe in words that which, in reality, is 
beyond the power of language. Above this 
stupendous cataract there is a navigation on the 
lakes of not much less than a thousand miles, 
11 



122 THE ST. LAWRENCE. 

takingthe average curve of the positions; and as the 
form of the group will be seen to be very irregular, 
they contain a great deal of shore, and have much 
influence upon the natural economy of the sur- 
rounding country, besides the advantage which 
they afford in the way of communication between 
the different parts. The extreme length from the 
northernmost point to the southernmost is not less 
than five hundred miles on the straight line. 

Below this there is still about five hundred 
miles of a vast river before the sea is reached, and 
nearly other five hundred before the wide estuary 
is arrived at. The mountains which bound this 
lower valley of the St. Lawrence, both on the 
north and the south, are not very elevated, but 
they are sufficient to cut it off from the action of 
the Atlantic on the south-east, and from that of 
the countries towards Hudson's Bay on the north. 
Thus, this valley, the lower extremity of which 
is turned in the direction of the icy sea, to the 
eastward of Greenland, and the upper end in the 
direction of the lakes, not only has a seasonal action 
in itself, alternating between south-west and north- 
east, but it in so far breaks the reciprocal action 
which would take place between the temperate 
and polar countries in those longitudes over which 
it extends. 

The third part of the northern division of this 
great central portion of North America inclines 
toward Hudson's Bay. It is a country in which 
there are no mountains, but an alternation of 
forests and swamps, with numerous small lakes, 
and abundance of rivers, though none of them are 
of any considerable magnitude. 

The third or remaining division of this part of 
the continent lies along the Mackenzie River, 



RIVER. 123 

which flows from Slave Lake to the Polar Ocean, 
its confluence with that ocean being in about 69° 
in latitude. The northern part of the country 
here is cold in the extreme during winter, while 
in summer it is very hot in proportion to the 
latitude. As in this part of the country there is 
no central elevation to interrupt the action over 
the whole latitude of the continent, the turns of 
the seasons are violent in the extreme. The snows 
in the early part of the winter fall speedily and in 
great quantity, but when they are over the air is 
tranquil, and the country may be travelled in all 
directions. At the commencement of summer 
again the snow melts rapidly ; but as the country 
is flat, the rivers do not very speedily discharge 
the accumulated water, and thus a great portion 
of it remains stagnant in the swamps ; and the 
quantity and vigour of vegetation are much 
greater than we should be led to suppose from the 
extremity of the cold in winter. In the extreme 
north, the spring floods, or "freshes," as they are 
termed, often roll down immense quantities of 
sand and gravel, which cover great masses of ice 
and snow, and so cut them off from the action of 
the atmosphere that, even in places where there 
is a surface vegetation in the summer, solid ice 
may be found upon digging a few feet into the 
earth. 

In all this country, both southward and north- 
ward, the annual waste of timber bears, of course, 
some proportion to the vast annual production ; 
and as there may be said to be a sweeping flood 
once a year passing over great part of the surface, 
the quantity of timber borne down by the rivers 
is immense. All along the northern shore of the 
American continent the people find drift timber 



124 DRIFT WOOD. 

in far greater abundance than they require for all 
the purposes of their simple economy ; and the 
surplus is borne eastward along the margin of the 
polar ice, so that in Iceland, and the more dreary 
isles still farther to the eastward, in which not a 
single tree fit for domestic purposes grows, the 
few inhabitants of the habitable isles, and the 
occasional resorters to those which are not habit- 
able, are abundantly supplied with timber from the 
American forests, which is wafted to their shores 
without any labour or contrivance of man. Nor 
is this supply of timber a matter of the open shores 
only, or a matter of yesterday, for there are va- 
rious places where former deposits of this drift 
wood have been covered with earthy matters, and 
upheaved above the mean level of the sea, and at 
the salne time wholfy or partially changed into 
coal by the action of volcanic fires. 

The Atlantic portion of America, or that which 
extends from the mouth of the St. Lawrence 
southward to the Florides, and which is in some 
measure cut off from the central valleys through- 
out its whole extent, is an alternation of fertile 
lands and swamps, crossed by very many rivers, 
though none of them are of large size. In con- 
sequence of the vicinity of the Atlantic, and the 
general set of the current of water in this part of 
that ocean being from the tropical to the polar 
latitudes, the seasons in this coast country do not 
run quite so much upon extremes as they do in 
the central valley ; but it is of comparatively small 
dimensions, and of course plays a correspond- 
ingly small part in the economy of the earth's 
surface. 

North America, to the westward of the Stony 
Mountains, is also, generally speaking, a narrow 



WEST COAST. 125 

country, though it is much broken by lateral 
spurs of the mountains, which in many places 
descend to the sea coast in very irregular chains, 
forming valleys of equally irregular distribution. 
The sea opposite this part of the shore is very 
broad : and from what has been said of the near- 
ness of the mountains to the shore, the action of 
this great sea is confined to a comparatively nar- 
row stripe of land. The position of the mountains 
also, which at their northern extremity trend 
north-westward, intercepts the free communica- 
tion with the Polar Ocean ; and, from the joint 
operation of this cause and that formerly men- 
tioned, the whole influence of the eastern half of 
the North Pacific is concentrated upon a narrow 
portion of this coast. The result is, that in the 
rainy monsoon, or rainy season, during which, in 
consequence of causes hereafter to be mentioned, 
the ocean sends its seasonal rain clouds against 
this portion of America, they burst upon it with 
indescribable force, — fury far greater than that 
With which, as we have hinted, the monsoons 
from the Indian Ocean burst upon the elevated 
lands, on the western, or Malabar, coast of the 
Indian peninsula. 

This has very marked effects upon the country 
itself, and also upon some parts of that which is 
farther to the east. To the northward of the 
parallel of 42° the river Columbia may be traced, 
falling into the Pacific, and being by much the 
largest river on the western side of the whole 
continent of America. The different branches of 
this river flow in passages among the mountains, 
which, though very crooked and irregular, admit 
the action of the storms of the Pacific to the very 
centre of the mountains ; and it will be perceived 
11* 



126 THE COLUMBIA. 

that the sources of the principal rivers which 
flow towards the Gulf of Mexico and the Arctic 
Sea, lie immediately opposite to those of the 
principal branches of the Columbia, and that they 
are at no great distance from each other ; here, 
therefore, over an extent of at least one thousand 
miles from south-east to north-west, the Stony 
Mountains consist of a single chain ; and as the 
sources of the rivers, as is almost invariably the 
case, overlay each other, the action of the Pacific 
tends to the supply of water for the rivers of the 
central valley, both northward and southward, 
as well as for those which flow to that ocean 
itself. 

But, to the southward of the mouth of the 
Columbia, the country assumes a different cha- 
racter, as the mountains there divide into two 
branches, one following nearly the line of the sea 
coast from about latitude 45° to latitude 23°, an 
extent of about fifteen hundred miles, their sum- 
mits being, upon the average, about six hundred 
miles from those of the main chain of the Stony 
Mountains. The Gulf of California extends into 
the southern part of this country for nearly the 
half of its length, at which place the two ridges 
are nearer to each other than they are to the 
north, and as the gulf is about a hundred and fifty 
miles wide for the first third of its length from 
the entrance, the country here is on both sides 
tolerably well supplied with water during the 
rainy season ; but to the north there is a sort of 
Sahara on a small scale, where the rivers almost 
disappear during the dry season, and some of them 
are lost in lakes or marshes strongly impregnated 
with salt. 

As the current of water from the tropical re- 



WEST COAST. 127 

gions circulates freely in the Pacific, the tempera- 
ture on this side of America is higher than it is 
on the east coast, or in the centre ; and as the rains 
of the Pacific are, for the greater part of the line 
of coast, confined to a comparatively small breadth 
of country, they fall with great violence, and 
sweep all the soil from the summits and slopes 
into the hollows. This constant renewal of the 
soil, together with the excessive humidity, gives 
a vast impulse to vegetation in this part of the 
world, and trees grow to a greater height than 
in any other regions-two hundred and fifty £eet, 
or even three hundred, is said to be no uncommon 
height for the pines of California, and they attain 
a diameter of fifteen or sixteen feet at the base, 
so that a room of considerable dimensions might 
be worked out of the solid. In general the cli- 
mate here is very hot, and the only inconvenience 
which the inhabitants sustain is from the violence 
of the rain storms, against which some tribes are 
said to defend themselves, not by huts, but by 
thatching themselves with a roof of long leaves, 
reeds, or grass, tied together at the top, and put 
over their heads and shoulders. 

There are, however, so many peculiarities in 
this part of the American continent, that it is im- 
possible even to name by far the greater number 
of them ; we must, therefore, just glance at the 
southern portion of America, and then proceed 
to the other parts of our subject. But still, the 
position of North America upon the globe ; the 
complete division of the west coast country from 
the rest by means of the Stony Mountains ; the 
extent of the valley of the Mississippi, the vast 
quantity of water which descends that river, its 
winding course, and the continual destroying and 



128 NORTH AMERICA. 

reproducing of portions of the land on its banks, 
the immense quantity of alluvial matter which is 
deposited in the lower valley ; and the connexion 
which this valley has with the regions of the 
north, through the lakes and swamps of the mid- 
dle latitudes ; all these, with a number of other 
circumstances, tend to render North America a 
highly interesting portion of the world ; and this 
interest is by no means diminished by the reflec- 
tion that this, the country of so much power and 
capability in a natural point of view, is the one 
where the triumph of human industry over wild 
nature is at once the most recent and the most 
remarkable. When we look upon the eastern 
hemisphere, we find that many of its districts are 
the monuments of mighty nations which have 
ceased to exist ; but in America, we have, as it 
were, the beginning of a nation in one year, and 
its maturity in the succeeding one. 



129 



SECTION VI. 

GENERAL FEATURES OF THE EARTH. AME- 
RICAN CONTINENT CONTINUED. 

That portion of the map of the world which 
now claims our attention, presents the most splen- 
did features, and displays the workings of nature 
upon a more magnificent scale than any which 
we have yet passed over in our hasty review. 
In respect of the vast extent and stupendous ele- 
vation of its mountain ridges, of the depth and 
sublimity of the valleys and ravines by which 
these are cleft asunder, of the violence of the 
storms which rage on their summits, of the num- 
ber and grandeur of the volcanoes which blaze 
amid their ever-enduring snows, and of the ex- 
tent to which those nether fires shake the earth 
to pieces by their violence — to say nothing of 
the immense stores of the precious metals which 
they contain, and which, in many instances, can 
be procured only by men whose drink is the 
mountain snow, and whose dwellings are inacces- 
sible for fully one half of the year, and then only 
with the extreme both of labour and of peril — 
there is no portion of the earth's surface which is 
at all comparable with South America. So, also, 
in no part of the world are there to be found 
rivers of the same sea-like magnitude which do 
not roll with foaming currents, — as is the case 
with the Mississippi, which renders the land on 
its banks unstable and uninhabitable, — or, as is 
the case in the St. Lawrence, present dangerous 
rapids and impracticable waterfalls, but roll pla- 



130 SOUTH AMERICA. 

cidly on, and offer, for the purposes of safe and 
easy navigation and intercourse, pathways of 
more than two thousand miles into the interior 
of at once the most extended and the most fertile 
basin on the face of the earth. Nowhere is the 
soil over so great a breadth of land so indescrib- 
ably rich — nowhere are the forests the same 
depth, the same ornamental beauties, or the same 
numbers of inhabitants. In short, if we would 
see the majesty of the material creation — the 
giant of geography, it is to South America that 
our attention must be directed. 

Before, however, we can throw our rapid glance 
over this singularly inviting continent, we must 
take up the connexion from North America ; for 
the narrow part of the country which lies between, 
bounded on the west by the Pacific, and on the 
east by the Gulfs of Mexico and Honduras and 
the Caribbean Sea, has general characters, differ- 
ing not only from the rest of continental America, 
but from every other part of the world. The 
details belong to particular geography, and, in so 
far as relative position is concerned, they may be 
learned from the map ; so that we shall consider 
the whole of this country under the general ap- 
pellation of Mexico. It may be considered as 
extending from about the parallel of 30° north, to 
about 9° north and 79° west, where, between the 
Bay of Mandingo on the Atlantic shore, and that 
of Panama on the Pacific, the isthmus is nar- 
rowest ; and here, North America may be said, 
technically speaking, to terminate, and South 
America to commence. 

If, however, we regard it according to its na- 
tural characters, which is the proper view, — if 
we are to look upon the map of the world as an 



MEXICO. 131 

instrumentof instruction, — thebest account which 
could be given of any other country would afford 
us no adequate notion of this one. Upon observ- 
ing it on the map, it will be seen that the two 
great oceans here approach very closely to each 
other, and that, for more than half the extent of 
the country, the average breadth from sea to sea 
is not much greater than that of England, while 
in many parts it is less. Now we know, from 
direct observation, than the action of the Atlantic 
extends not only over England, but over the 
eastern sea, and to a considerable portion of 
continental Europe beyond ; for the prevailing 
winds are from the west. In Europe, the ac- 
tion of the Atlantic is but the secondary, or re- 
turning current, and it is in latitude considerably 
removed from the direct action of the vertical 
sun, even during the height of summer ; while all 
the narrower parts of Mexico lie within the tro- 
pic, and are in the line of the full set of the pri- 
mary current, uninterrupted, not only from the 
coast of Africa, but from the Cape of Good Hope, 
and the ocean beyond. Hence we might suppose 
that the Atlantic and Pacific would alternate with 
each other upon this narrow land, and carry al- 
ternate seasons of rain, in turns, over the whole 
of it, thus giving it the same glades of exuberant 
verdure, the same spice-clad hills, and the same 
marshes, rank with forests of reeds, which we 
meet with in those oriental islands, where the 
Pacific and the Indian Ocean alternately answer 
to each other's call, and keep nature continually 
awake and working, by the play of shifting mon- 
soons between the east and the west. 

Such, however, is not the case : there is no 
communication by means of the atmosphere, even 



132 MEXICO. 

at the narrowest part of this land, between the 
Atlantic and the Pacific ; and not only so, but the 
direct action of each is confined to a comparatively 
narrow stripe of land along its own shore. The 
reason of this will become abundantly apparent, 
from the physical structure of the country. 

On the parallel of the northern part of the Gulf 
of Mexico, the eastern ridge of the Stony Moun- 
tains subsides ; and though the country is still 
elevated in the centre, it can hardly be said to be 
mountainous. Here there is little action of either 
ocean ; and as there are no lofty summits to trea- 
sure up humidity in snow, or even to assist in 
condensing and collecting it as rain, the surface 
is, in many places, burnt up in the dry season, 
and, as already said, there are portions of it per- 
manently desert, destitute alike of water and of 
vegetation. As the continent begins to narrow, 
the elevation increases ; and there are some ridges 
of hills, covered with pine forests and interspersed 
with plains, which are inhabited by numerous 
herds of wild horses, and men who are still more 
wild, for they are the renegades of all the sur- 
rounding countries. The coast in this place, for 
about half way south on the Gulf of Mexico, may 
be considered as in some respects a continuation 
of the central valley of North America, and un- 
der the influence of the northward and south- 
ward seasonal action which takes place there; 
and, after this point is passed, the interior of the 
country has acquired an elevation, upon the ave- 
rage, of not less than about 5000 feet, altogether 
independently of the mountains, some of which 
attain an altitude of more than 15,000 feet. 
This elevated central country forms the table 
land of Mexico, which extends, varying in height 



MEXICO. 133 

and breadth, along the whole of the narrow part 
of the continent, so as completely to cut otf, not 
only the mutual action of the two seas, but the 
action of each upon the central country, which is 
thus thrown upon its own resources, with little 
or no connexion in the general action of the 
globe. Over this singular land, there are scat- 
tered many mountain peaks, and several consi- 
derable ridges, the summits of which are above 
the line of perpetual snow, and on which, even 
to a considerable way downward, the weather 
is excessively severe ; but the general aspect is 
that of a number of valleys, or, strictly speaking, 
basins, or shells, which do not open to the sea, 
and from which, consequently, no rivers are dis- 
charged. Some of these still contain lakes, in 
their central or lowest parts ; and near the city of 
Mexico there is a lake of considerable dimen- 
sions : almost all of them contain stagnant pools 
for a short time during the rains ; and they give 
evidence of having been at one time the basins 
of lakes of considerable extent ; and at that period 
of its history Mexico may have been a well-wa- 
tered country, covered with an abundant vege- 
tation, and, though within the tropics, having a 
climate as cold as that of the upper valley of the 
Mississippi, if not colder. The deposits of salt, 
and also of the remains of aquatic animals, which 
are found in the bottoms, are sufficient proofs 
that there has once been abundance of water 
there ; and the fact of there being no outlets to 
the sea, forbids us to suppose that the waters of 
the ancient lakes of Mexico can have found their 
way along the surface of the earth to the general 
receptacle of the waters. 

Hence arises the question — what has become 
12 



1 34 MEXICO. 

of those waters? and wherefore is it that so much 
of the surface of this apparently once fertile coun- 
try is now mantled in desolation and sowed with 
salt? There are two ways, and it may have partly 
gone by each of them. In the first place, the 
shore countries, both on the east and the west, are 
exceedingly hot ; and though the seasonal rains 
fall with great violence, they last for only a small 
portion of the year. The table land, though more 
elevated, and therefore not so warm as the shore 
countries, is still tropical. The season of rain on 
it is short, and therefore, under any state of things, 
the evaporation produced by the heat must have 
drank up much of the moisture of the surface ; 
and as we shall be better able to explain after- 
wards, the more that the surface of any country 
is covered with tall and growing vegetation, the 
greater is the quantity of moisture which is turned 
into vapour. It is another general law, that air 
from a colder district, although saturated even to 
the point of depositing its moisture in rain, be- 
comes absolutely a drying or evaporating atmos- 
phere when it is carried to a surface which is more 
heated. For instance, the east winds, in the early 
part of our summer, which come across the east- 
ern sea, are really charged with a considerable 
quantity of moisture, but they do not rain upon 
the comparatively dry plains of Norfolk, Suffolk, 
and Essex ; they pass over these in cold and 
withering drought, and discharge their humidity 
on the more midland and elevated parts of the 
country. Upon these principles, the hot coun- 
tries on the Mexican shores must every year 
withdraw a portion of water from the interior ; 
and thus the ancient Mexican lakes may be said 



MEXICO. 135 

to have been in part drained, and the modern ones 
in part draining, through the sky. 

Secondly, this table land is full of volcanoes. 
The craters, or rather the chimneys of some of 
these, may penetrate the earth to a depth consider- 
ably beyond that of the bottom of the sea. Indeed, 
it is probable that all volcanoes, and all volcanic 
action, result from connexion with the sea; be- 
cause we have no remarkable volcano at any very 
great distance inland ; and because, where the sea 
appears to have evidently receded from volcanic 
countries, the volcanoes are all extinguished. 
Thus there are extinct volcanoes in the mountains 
towards the south of France ; and we have the 
evidence of vast accumulations of sand, and sea 
shells, and even the distinct markings of successive 
beaches, lo prove that the sea has, in the course 
of ages, retreated a great way in that country. 
Now, it is easy to understand how the chimneys 
of these volcanoes, and the cracks and fissures 
produced by earthquakes, which are general con- 
comitants of volcanic action, and not unfrequently 
take place in their greatest violence between the 
volcanoesand the sea, thereby further provingwhat 
we have staled, may, indeed must, have acted as 
under-drains to the table land of Mexico, and thus 
accelerated the progress of drought and desolation. 
Farther, it is a remarkable fact, that there are in 
the sea between the Mexican shores and the 
island of Cuba, fountains of fresh water, which 
are discharged from the bottom with so much 
force that they boil over the surface so violently 
as to be dangerous for light boats, and so perfectly 
unmingled with the water of the sea, that sailors 
are sometimes in the habit of drawing fresh water 
from them with pitchers. The water of those 



f 



136 SUB-MARINE SPRINGS. 

sub-marine springs is cold ; it is accompanied by 
no discharge of vapour; and, as was ascertained 
by Humboldt, there are fishes found in it which 
are not natives of those seas. Therefore, this 
water must descend through fissures in the earth 
somewhere : those fissures must be of sufficient 
size to admit the passage of the mainland ; and 
consequently, nothing but the pressure of a head 
of water, in the same manner as makes an ordi- 
nary fountain to cast up its jet, can produce those 
sub-marine springs. This head of water must 
also demand a very considerable elevation, in 
order to clear its way to the surface, through the 
ocean water, unmingled with that water, and 
where, — as is the case between Cape Catoche in 
Yutacan, and Cape St. Antonio in Cuba, — the 
current of the ocean runs with much velocity and 
force. Those springs are, no doubt, nearer to 
Cuba than to any part of Mexico, and therefore 
they may be supplied from that island ; but if the 
fact is admitted in the case of Cuba, it cannot be 
denied in that of the Mexican table land. 

These circumstances — though in the notice of 
them we have been obliged to anticipate some 
principles, the full understanding of which requires 
a knowledge of the general laws of action both of 
the air and the sea — are yet very necessary to be 
borne in mind, in order that the reader may fully 
understand that progress of nature which has 
brought some very large portions of the land to 
that condition in which we now find them. If 
the reader has attended to what we have stated 
respecting much of central Asia, the greater part 
of northern Africa and of New Holland, and 
partially of all places which are cut off from com- 
munication with the sea, he will at once perceive 



PROGRESS OF DROUGHT. 137 

that there has been by some means an abstraction 
of the water from those places ; and that though, 
in such as have been volcanic and have contained 
much moisture on the surface, the volcanic action 
may have occasioned an under-drainage, — yet, 
after a certain stage, that drainage may be sup- 
posed to cease, and to cease the sooner the more 
tropical, and therefore the warmer, the climate. 
After vegetation is in a great measure gone, except 
those saline plants which are the last to quit the 
desert, a few weeks of periodical rain, occurring 
once in the year, must rather hasten then retard 
the final catastrophe. Those rains which, in 
places cut off from the sea are derived from the 
country itself, either in its remaining brooks and 
pools and vegetation, or from the mountains which 
enclose it or are upon it, not only wash the little 
soil there is from the parched surface, but afford 
an evaporation, and at the same time cool the air, 
and send it loaded with its moisture, in part at 
least, out of the country. The violence with which 
rain falls is generally in proportion to the resist- 
ance offered by the dryness and warmth of the 
earth ; so that while we have gentle showers upon 
thick forests and green savannahs, we have in the 
very same latitudes pelting torrents, which sweep 
everything before them, upon the barren plains 
and the bare mountains. It seems, indeed, and 
it is in accordance with the general benevolence 
and beauty of the system, that the rain of heaven 
which falls upon the fertile land to refresh and to 
nourish, comes upon the sterile track to rend its 
mountain rocks, break its stones into sand, and 
sow its valleys with salt. The saline plants 
greatly assist at this stage of the progress; and 
though there is no part of the table land of Mex- 
12* 






138 EASTERN SHORE. 

ico which has yet become drifting sand like 
Sahara, there is much of it covered with saline 
deposits, beyond all human power to restore to 
any degree of fertility, and therefore given up to 
utter barrenness and ruin, until some of the more 
mighty movements of nature, the period of which 
does not fall within the brief span of human 
history, shall remodel it, reclothe it with vege- 
tation, and repeople it with life. From the pe- 
ninsula of Yutacan southward, the east coast is 
exposed to the direct current from the Atlantic. 
Yutacan itself is narrow and less elevated than the 
country to the westward, so that the atmospheric 
current sweeps across, and Yutacan is covered 
with luxuriant forests in all the lower parts. 
The same applies to the countries round the Gulf 
of Honduras, a little to the south ; but when the 
most easterly point of the Musquito shore is 
reached, the northern part of South America both 
meets the current, and bends it to the north, so 
that for great part of the year the surface is burnt 
up. Along this shore, where the intensity of the 
Atlantic current acts with all its force upon a 
small breadth of land, the rains, though not of 
very long continuance, are unequalled in their 
violence ; so that in the course of an hour or two 
the hollows are fathoms deep in water, rolling 
and roaring with the utmost fury, and bearing 
down everything save the strongest and most 
deeply rooted trees. The West India Islands, as 
may be seen from their position in the map, form 
a sort of guard to this coast, and they have their 
share of the violent action of nature to which it is 
subjected. 

We shall now glance at America from the 
Isthmus of Panama southward ; and here, though 



THE ANDES. 139 

the rivers are majestic and well defined, the great 
ridge of the mountains form the most striking as 
well as the most general feature. As will be 
seen from the map, those mountains are nowhere 
at any considerable distance from the shore of 
the Pacific, and the coast country there is a mere 
border, in which there is no river worthy of 
notice in a general, sketch. Generally speaking, 
the Andes follow the line of the coast very ex- 
actly, and they attain their greatest elevation in 
about the middle length of the country, that is, 
in about 16° south latitude. Immediately under 
the equator there is a sort of central point whence 
the mountains diverge, one branch running north- 
eastward in the direction of Trinidad; and we 
may imagine a continuation through the West 
India Islands till we come to Yutacan, and thus 
we have a basin wholly land-bound on the one- 
half of its circumference, and partially so on the 
other, and including within it the Caribbean sea ; 
another branch keeps the line of the Pacific 
shore, and diminishes in height as it reaches the 
Isthmus of Panama. Several other ridges diverge 
from these, all directed northward, and separated 
from each other by very deep and highly romantic 
valleys, which are in some places so narrow, and 
their boundaries so steep, that the width is scarcely 
more than the depth. From the equator to about 
6° south, the summit of the Andes, that is, the base 
of the individual peaks, forms a sort of table land 
bearing some resemblance to that of Mexico, but 
resembling more a very elevated valley between 
two ridges of mountains. We may mention that, in 
the Spanish language, a ridge of mountains which 
stretches in line, whether straight or crooked, 
without being broken into rugged peaks, is called 



140 THE ANDES. 

a cordillcra ; and where the chain of the Andes 
runs double, as it does in this part, the ridge next 
the Pacific is called the Cordillera of the coast, 
and the second the Cordillera of the interior. 

In latitude about 15° south, the great chain of 
the Andes branches again, and the ridge of the 
interior, taking a sweep northward of about 70 
miles, again returns parallel to the ridge of the 
coast, and the two enclose between them a singu- 
lar upland valley, in which there is situated the 
lake of Titicaca, from which the river Desagua- 
dero flows southward, and is lost by evaporation 
in a sandy desert in about latitude 19°, or about 
one hundred miles north-west of the celebrated 
silver mines of Potosi. The eastern or interior 
ridge here consists of perhaps the most lofty moun- 
tains on the face of our globe, though it is only 
lately that they were known, and consequently 
they have not been accurately measured. Those 
that have been measured, however, have an ele- 
vation of not less than twenty-four thousand two 
hundred feet, which is only one thousand five 
hundred less than the most elevated of the Hima- 
laya ridge, the mountain of Dhawalaghiri ; and, as 
this mensuration did not extend to the snowy 
summits of Sorate, between 15° and 16° south 
latitude, which are the most elevated of the whole, 
there is reason to believe that these mountains are 
still more lofty than the highest in Asia. 

The chain of the Andes varying in elevation 
at different places, but still retaining a height at 
which there is snow almost all the year round, 
not only on the peaks, but in passes by which 
the ridge can be crossed from east to west, stretches 
onward to the very southern extremity of the 
American continent, still at only a small distance 



THE ANDES. 141 

from the shore of the Pacific, though, from about 
latitude 28° to 42°, the average breadth of the 
country from the summits to the sea may be es- 
timated at about one hundred and fifty miles. 

A mountain ridge of so vast an elevation, ex- 
tending the whole length of South America, and 
being, generally speaking, not more than one 
hundred miles from the shore, must effectually 
cut off all the breadth of the country to the east- 
ward, that is, the entire continent, except a mere 
border on the west, from the action of the Atlan- 
tic, and also confine that of the Pacific to the 
stripe of land which lies along its own shore. It 
so happens, too, that the sources of the principal 
streams lie to the westward of the most elevated 
summits, while the courses of the rivers, of 
which these streams are the feeders, are di- 
rected towards the east. This cuts the small 
stripe of land, consisting of Peru, some interme- 
diate tracks which are nearly desert, and Chili, 
from all reciprocal action of nature, and indeed 
from all general intercourse of man and man, 
with the eastern part of the continent, which in 
a general view may be considered as more emi- 
nently deserving the name of South America. 
Thus we are to regard the country as inclining 
to the shores, which the map points out to us, 
being to the north-east, the east, and the south- 
east; an idea of the natural divisions of which 
may be readily formed by examining the courses 
and lengths of the principal rivers. 

Leaving out the minor ones, there are three 
of these which indicate the centres of three re- 
markable portions of the country, the Orinoco, 
which discharges its waters into the Atlantic by 
a number of mouths, the principal one of which 
is about G0° west longitude, and 9° north latitude ; 



142 RIVERS OF 

the Amazon, which discharges into the sea, im- 
mediately under the equator, and in about 50° 
west longitude, a larger volume of water than 
probably any other river on the surface of the 
globe ; and the Plata, which pours its stream into 
a wide estuary in about 14° south and 59° west, 
nearly on the same meridian with the principal 
mouth of the Orinoco. Between those rivers 
there are ridges of mountains, some of which 
would be considered both extensive and elevated 
in many parts of the world, but they sink into 
nothing as compared with the gigantic Andes, 
and none of them can be considered as a continu- 
ation of, or as connected with, that mighty ridge. 
Between the Orinoco and the Amazon there are 
heights, the general direction of which is east and 
w T est; but at about longitude GG° they subside, so 
that the brandies of the one river come near to, 
and are said to be in some instances connected 
with, the branches of the other; and to the east- 
ward those heights are interrupted by swampy 
places, upon which the water stagnates to a great 
extent during the rainy season. 

Between the Amazon and La Plata the moun- 
tains are much more irregular. From Paraiba, 
on the north coast of Brazil, in about 41° west, a 
ridge commences and runs nearly parallel to the 
east coast, and about three hundred miles distant 
from it, to about the 20° of south latitude, where 
it turns eastward and joins another ridge, which 
may be traced northward on the right bank of 
the river San Francisco to about the latitude 10° 
south ; and from the junction of these — which 
forms an elevated district of sterile character, but 
containing the rich diamond mines of Brazil — 
another ridge extends southward to the estuary 
of La Plata. 



SOUTH AMERICA. 143 

The central elevation, where the waters of the 
Amazon and La Plata divide, is very irregular, 
as some of the branches of the Amazon rise as far 
to the southward as 20° latitude, and those of the 
Paraguay, or central stream of La Plata, at least 
five hundred miles farther to the north. The cha- 
racter of the country at which the waters divide 
between those great rivers is as irregular as its 
position in latitude; sometimes it consistsof moun- 
tains, or, more strictly speaking, of hills,andsome- 
times of plains, which are flooded during the rainy 
season, and burnt up during the dry. 

Of these great divisions of South America, the 
most interesting beyond all calculation is the 
valley of the Amazon, — a valley which contains 
more than half as much surface, and probably 
more fertile land, than the whole continent of 
Europe, and compared with which the Valley of 
the Nile, long and much as it has been celebrated, 
is a mere line, and such valleys as those of the 
Danube and the Ganges are only little patches. 
The length of this valley, on the straight line 
from east to west, is little short of two thousand 
miles, and its breadth from north to south is very 
little less, and this not at a few detached points 
only, but very nearly for the whole range of the 
length, and certainly for two-thirds of it. Nor 
is there within this vast extent of country any 
district of even moderate extent sterile, or inca- 
pable of being reclaimed from sterility ; and the 
whole is so little elevated above the mean level of 
the sea,that the river and its principal branches are 
navigable for the greater part of their length, and 
the western ones up to the very gorges by which 
they issue from the Cordillera of the Andes, and 
in some instances beyond. Those branches, too, 



144 THE AMAZON, 

roll no stinted tides, and no merely seasonal wa- 
ters. The western branches drain both sides of 
the Cordillera of the interior for an extent of at 
least twelve hundred and fifty miles ; and the sum- 
mits are every where above the line of perpetual 
snow, so that the waters which flow thence know 
little abatement at any season of the year. In 
Upper Peru, or Bolivia, that is, the country im- 
mediately to the east of the Andes, the large 
rivers which unite to form the main stream of 
the Amazon are almost countless; and farther to 
the eastward the branches on this, the right-hand 
bank, would be accounted rivers of the first mag- 
nitude in almost any other part of the world. 
The Madera, which rises about 20° south latitude, 
near the mountains of Potosi, has a course of not 
less than one thousand four hundred miles, which 
the windings will bring up to not less than two 
thousand. The Topayos and Xingu, though in- 
ferior to the Madera, are large rivers; and they 
are exceeded by the Tocantins, which, consisting 
of two large branches, drains the western parts 
of Brazil. On the left bank the rivers are not 
of such gigantic dimensions ; but still the Yupura 
and the Rio Negro rival in magnitude the largest 
rivers in the European continent. 

The Orinoco is a small river compared with the 
Amazon ; but still its length and volume of water 
are very considerable, though, as its valley does 
not open so immediately upon the current of the 
Atlantic as that of the other, the plains in the 
upper part, which are also in some instances more 
elevated, are more liable to be burnt up during 
the dry season. Still the lower valley of the 
Orinoco, the country between that and the Ama- 
zon, and great part of the coast of Brazil, are 



AND ITS BRANCHES. 145 



remarkable for the luxuriance of their forests, and 
the vigorous growth and exquisite beauty of many 
of the climbing plants, and plants with bulbous 
roots, with which those forests are adorned. 

The upper country, too, is one continuous 
forest, extending along the eastern slopes of the 
Andes from about 4° north of the equator to little 
less than 20° south, and reaching down the coun- 
try to an extent which has only been explored at 
certain points, but which is everywhere very 
great. This is, in fact, the very home of vegeta- 
tion ; and as the action of the Atlantic current 
reaches the Andes, and is returned by the floods 
of the low countries during the rains, and the 
melting of the snows during the droughts; and 
farther, as the course of the rivers during the 
greater part of their extent is slow and placid, 
there are evidently fewer of the elements of wear- 
ing out in this valley of the Andes than in any 
region with which we are acquainted ; while, 
from the number of its rivers, their magnitude, 
and the comparative flatness of the intermediate 
land, there is no region upon the face of the globe 
which could be so completely connected together 
by means of artificial navigations. Besides, the 
climate is exceedingly warm, and the soil equal 
to the growth of every imaginable production 
requiring a situation of the most favourable kind ; 
and though the great inland chain of the Andes, 
in consequence of the labour of reaching it from 
the western sea, is comparatively little known, it 
is well understood that the mountains there are 
far more rich in the precious metals than in the 
countries farther to the north. 

There is one remarkable point in this part of 
South America, and that is, the situation of the 
13 



146 CENTRAL LEVEL 

celebrated mountains and mines of Potosi. These 
are detached from the great chains of the Andes, 
and situated nearly under the twentieth degree of 
south latitude, and between 65° and 66° west lon- 
gitude. In the maps, except those of very modern 
construction, these mountains are laid down con- 
siderably to the westward of the true position, and 
therefore an improper notion is given of the shape 
of this part of the country; but in as far as the 
division of the great waters is concerned, the 
summit level as between the Amazon and La 
Plata, and also the internal marshy desert, in 
which the Desaguadero is lost, may be considered 
as situated near Potosi ; for Rio Grande, a branch 
of the Madera, rises immediately to the north, and 
the Pilcomaya, a branch of La Plata, immediately 
to the south ; while there flow towards the west 
some small streams which are lost in the same 
desert which drinks up, or evaporates, the waters 
of the Desaguadero. 

To the southward of this summit level we come 
into the plains of Paraguay, or those situated in 
the western half of the valley of La Plata; and 
these, not having the advantage of a similar current 
to that which plays along the valley of the Andes, 
are in many places sterile, or, at all events, naked 
of forests ; and this character of country continues 
down the centre of the southern part of the con- 
tinent till we come to the termination of the 
Pampas, or vast plains, which in general produce 
herbaceous vegetation only, the most conspicuous 
of which is alternate crops of clover and thistles ; 
and this termination brings us to about 40° south 
latitude. On the left bank of La Plata there are 
mountains of some elevation between the different 
branches of that river ; the sides of those moun- 



OF SOUTH AMERICA. 147 

tains are clothed with woods, and the bottoms 
afford rich pastures, in which countless thousands 
of wild cattle, the produce of stock originally im- 
ported from Europe, find abundance of food ; and, 
indeed, many parts of the country on the other 
side of the river is stocked in a similar manner, 
and in nearly the same abundance. 

The country southward of the Pampas is suffi- 
ciently narrow for being under the influence of 
both oceans; and though its surface is very irre- 
gular, it abounds with vegetation of a more tro- 
pical character than the latitude would lead us to 
suppose. Such is a very brief outline of the 
characters of the principal lands which are of 
sufficient extent for having much influence in the 
general economy of the earth's surface. 

But though the space to which this volume is 
restricted prevents the possibility of giving any- 
thing else than mere outlines of the more general 
features ; yet, in order that the reader may fully 
understand and duly appreciate the general subject, 
it will be necessary to acquire a knowledge of the 
details, at once extensive and accurate. Indeed, 
a knowledge of the earth's surface, down to even 
very minute particulars, is essentially necessary for 
every one, both as a portion of general education, 
and as a means of turning that education to ac- 
count in practice ; and probably the hasty survey 
which we have attempted to take may induce 
many, whose geographical knowledge has hardly 
extended beyond the mere repetition of a few 
names, to acquire a knowledge of that science 
more consistent with its usefulness and the plea- 
sure which it is so well calculated to furnish. 



148 



SECTION VII. 

BRIEF ABSTRACT OF THE EARTH'S FEATURES. 

In the preceding sections we have taken a 
cursory and sketchy view of the great component 
parts of the earth's surface, as preparatory for 
examining the operation of those causes upon 
which the different climates and productions of 
its several regions depend. But before we pro- 
ceed to notice those causes, it may be desirable to 
bring to a sort of focus those elements which we 
have attempted to collect, as this will save some 
particular reference afterwards. The chief points 
to be attended to in the configuration of the earth's 
surface as affecting climate, are those which in- 
terrupt the communication between any region 
and the sea, and those which break the circulation, 
whether of sea or of air. In the latter case, the 
circulation may be broken either in the direction 
of east and west on a parallel, or north and south 
on a meridian ; and we shall see afterwards that 
the interruption on a parallel is of most import- 
ance in countries situated near the poles, and that 
on a meridian in countries nearer the equator. 

Leavingthe pressure of the atmosphere — which, 
by being sometimes greater at one place than at 
another, throws the ocean out of that shape which 
it would naturally assume if the waters were at a 
state of rest — we may mention that land, as be- 
tween sea and sea, always occasions an interrup- 
tion to some extent or other ; that if the land rises 
into mountainous ridges of any considerable ele- 



INTERRUPTIONS, 149 

vation, these occasion a greater interruption than 
would be produced by a far greater breadth of 
low and flat land, and if they rise within the region 
of snow they offer the same obstacle as an entire 
quadrant from the equatorial to the polar regions ; 
and that, independently of elevation of surface, 
surfaces of different characters, and clothed with 
different kinds of vegetation, offer different de- 
grees of interruption. Thus, if the surface is bare, 
and so situated that the sun beats strongly upon 
it, no current of the atmosphere can sweep over 
it, and therefore no influence of any other region 
can affect it to any considerable extent ; because 
such a surface rarefies and expands the air, gives 
it an upward motion, prevents it from depositing 
any moisture which may be in it, and at the same 
time draws toward itself the air on the surface of 
the ground all round it. If a surface of this kind 
is large, such as the desert of Africa, or of central 
Asia, or the table land of Mexico, the air which 
comes in from the surrounding regions is heated, 
rendered more dry, and thus conveyed, without 
producing rain, to distances more remote than 
those from which it fetches moisture while it is a 
surface current moving toward the desert. 

On the other hand, if the interruption is high 
land, and especially land which rises above the 
line of perpetual snow, it resists the current 
towards it ; or, if that current is powerful enough 
to reach the cold and elevated surface, it is con- 
densed there, and parts with its humidity, and so 
moves back again along the surface, generally 
speaking, as a cooling and dry atmosphere. 

When we apply these principles to what we 
have observed in examining the map, we find 
that the most extensive interruption on the me- 
13* 



150 INTERRUPTIONS, 

ridian occurs in America, where the Andes, and 
their continuation in the table land of Mexico, 
and the Stony Mountains, completely separate 
the action of the seas, and thus break any circula- 
tion that there may be from 55° south latitude to 
75° north, or, we may say, to the permanent ice 
of the Polar Sea, where of course all current and 
all circulation on the parallel is at an end. This 
interruption, in as far as the mountains are con- 
cerned, is nearly on a meridian from 55° south to 
10° north, or, in round numbers, for an extent of 
four thousand five hundred miles; and for the 
rest of their length, about as much more, they 
interrupt it in an oblique direction from south- 
east to north-west, extending in this way over 
only 5° less in latitude than in the south, and at 
the same time trending westward at their north- 
ern extremity over a full quadrant, or 90° of 
longitude. Notwithstanding this, there are 
comparatively few portions of the American 
continent which are cut off from the influence of 
the sea in every direction. On the northern part 
of the continent, the only part which is so, except 
when the Polar Sea is covered with ice and snow, 
and consequently has the same effect as if it were 
land covered with the same substances, the only 
portion which is so cut off, and the cutting off is 
not total, is the western half of the great central 
valley toward the = Stony Mountains, a portion of 
the country in Upper California, where there is a 
second ridge between the Stony Mountains and 
the Pacific, and the comparatively low country 
between the Stony Mountains and the table land 
of Mexico. These districts are, as we have seen, 
latitude for latitude, far less fertile than those 
which enjoy a communication with the sea. The 



SEASONAL ACTION IN AMERICA, 151 

parts of the central valley on the west, or right 
bank of the Mississippi, do not contain such 
dense forests as are found on the opposite bank, 
or such giant trees as we meet with on the west 
coast, in consequence of the trend of the moun- 
tains forming a protecting wall against the chil- 
ling blasts of the pole, the climate is, notwith- 
standing the violent seasonal rains, warmer than 
the same latitudes on the east. When rains do 
occur on this eastern side of the Stony Mountains 
it is natural to suppose that they fall with more 
violence than on the other bank of the river ; 
because the rocks and naked plains are more 
intensely heated and more speedily cooled than a 
surface covered with luxuriant vegetation. We 
find also that, as we approach the river, the 
country on this right-hand side possesses naturally 
some advantages over that of the left. On this 
latter situation the forest in its natural state came 
down all the way from the Rhodadendron groves 
of the eastern mountains to the very bank of the 
river, and even into its current whenever that 
threw a bar of new land or afforded anchorage 
for a drifting tree ; and whether it was campagne 
or marsh, there was found a species of wood 
adapted to it. No doubt the action of the river 
and the eddying of the winds throw up "bluffs" 
or sand hills, on this side as well as on the other, 
and upon the more arid heights, which did not 
afford depth of rootage for a large tree, and were 
not of a mossy nature enough for the mountain 
shrubs, were open blades, with here and there a 
scattered tree, forming what the Americans, 
adopting the French phrase, not very happily 
term "prairies;" but there were originally no 
such wide savannahs as those which afforded 



152 SEASONAL ACTION IN AMERICA. 

grazing for the innumerable herds of the Ame- 
rican bison on the western bank of the river. 

In the central part of America, namely, that 
from the parallel of the Gulf of Mexico to the 
Isthmus of Panama, the whole of the table land 
is cut off from connexion with the seas ; and it 
may be regarded as a mountain interruption. 

In South America, the whole continent, with the 
exception of a small stripe along the western shore, 
is cut off from the Pacific ; and, though it were not, 
the action of the Pacific here is not toward the 
land, but in a line parallel to the shore. Hence, 
even over this long and narrow district, the action 
of the sea and land upon each other is very trifling ; 
and the progress of the whole western country 
may be considered as one toward barrenness and 
drought. Wherever there is moisture, this portion 
of America is very fertile, and the climate is de- 
lightful ; though, from theproximity of the Cordil- 
lera to the sea, and the strong volcanic action 
which is constantly going on at different points of 
that Cordillera, through great part of its length, 
the country on the shore of the Pacific is liable to 
dreadful calamities from earthquakes. From the 
extent of the valley of the Amazon, both in length 
and in breadth, there is little room for lands un- 
affected by the action of the sea to the eastward 
of the Cordillera of the Andes. The spots at 
which this action is not felt, and which are in con- 
sequence parched and burnt up during the season 
of drought, are the elevated plains on the upper 
part of the Orinoco. The desert, which drinks 
up the Desaguadero, to the southward of that sin- 
gular valley between the double Cordillera of the 
Andes which contains the lake of Titicaca, was 
the cradle of Peruvian civilization, and most like- 



THE EASTERN CONTINENT. 153 

ly the place which sent the romancing adventur- 
ers of the earlier ages of discovery to seek, in a 
more northerly and easterly part of South Ame- 
rica, an El Dorado — a city paved with gold, and 
having its buildings roofed with the same costly 
material ; this mountain valley, and the country 
to the south of the summit level, between the 
sources of the Madera and Pilcomaya, until the 
Pampas is passed over, and the mountainous re- 
gion of Patagonia arrived at, are the only portions 
of South America which are not, to some extent 
at least, subjected to the influence of the sea. 

On the eastern continent we have, in the first 
place, Africa, breaking the continuity, in the di- 
rection both of the latitude and the longitude ; al- 
though we know too little of the nature of South- 
ern Africa, from 10° north and 20° south of the 
equator, to be able to state its specific effect. We 
do know, however, that the surfaces, both of 
Africa and New Holland, are sufficiently powerful 
for changing the current in the Indian Ocean into 
monsoons, alternating between those countries and 
the south of Asia. 

In Europe, the obstacles presented by moun- 
tains chiefly affect the action in the direction of 
the latitude, and cut off communication with the 
cold regions at the pole ; while great part of the 
continent is open to the action of the Atlantic 
on the west. In Asia the deserts and the moun- 
tain ridges cut the centre of the continent com- 
pletely off from all influence of the sea on the 
south : and the mountains and deserts to the west- 
ward of China, though the particulars of them are 
imperfectly known, form a barrier equally com- 
plete between central Asia and the Pacific. It 
should seem that the mountains which separate 



154 THE EASTERN CONTINENT, 

Siberia from the countries to the south form a less 
perfect barrier against the Siberian cold ; for 
though China is warm in the summer, the winter 
at Pekin, which is nearly on the same parallel 
with Madrid, or rather to the south of it, and not 
nearly so high above the level of the sea, is much 
colder than it is even in France. 

These recapitulations will serve as a sort of 
artificial memory of the features of the land, upon 
which the general characters of the great divisions 
are founded; and if these are once fully understood, 
the more minute particulars can be worked out 
by any one who attentively studies the details of 
geography. We have not noticed any of the 
smaller islands which lie scattered over the wide 
ocean, because these in general partake of the 
uniformity of the ocean itself; and, generally 
speaking, they are more fertile and more healthy 
than the broad lands, and never liable to be burnt 
up with drought. The reason of this last circum- 
stance is, that in those small spots there is a sea 
air, sufficiently charged with humidity, always 
ready to blow from the shores, when the surface 
of the land becomes heated. Thus, there is no 
such great differenee between season and season 
in the islands as we meet with in the continents, 
especially those parts of the continents which are 
either cut off from the action of seas, or have an 
uninterrupted play of currents between the tropi- 
cal and the polar regions constantly passing over 
them. When we once have obtained a know- 
ledge of those constituent surfaces of the earth, 
upon which any agencies can act, as producing 
differences between region and region, in produc- 
tiveness, in healthiness, in beauty, and in every 
thins which can render them desirable as the 



the earth's surface. 155 

residence of man, or show man how he can im- 
prove their natural imperfections in his little way, 
we are next to inquire what the agencies are that 
act differently upon those different surfaces. 

This is a far more difficult part of the subject, 
and one of which our knowledge may be said to 
be in its infancy ; inasmuch as we know not all 
the agents which conduce to this end, and we 
know not how the one of them may modify the 
action of the other, or how, under the operation 
of the same agent, district may conspire with, or 
conspire against district, so as to produce a result 
different from what there would be if either of the 
districts were acted upon without the other. 



156 



SECTION VIII. 

AGENTS AND INSTRUMENTS IN THE MORE GE- 
NERAL PHENOMENA OF THE EARTH. 

In treating of these, it will be necessary, in the 
meantime, to limit our consideration to the present 
state of our abode — to the earth as it now presents 
itself to our view, without including any of those 
agencies by which the solid strata of which it is 
composed, have been moulded into their present 
forms, tempered to their present consistencies, 
placed in their arrangements, and disposed in those 
localities, which the map shows that they occupy. 
The knowledge of these latter questions is still in 
its infancy ; and from the little that has happened 
within the period of recorded history, we may 
conclude that many generations of men must be 
gathered to the dust before there are any remark- 
able general changes in the general aspect of the 
earth. 

But those who wish to write popularly, so as 
to afford a little instruction to all who may stand 
in need of it, must write for the day, and of the 
day ; and as the world as we now live in it — 
and not as it was before we were born, or it shall 
be after we are no more for its enjoyment — is the 
living book of our instruction, the volume which 
the Almighty has spread wide defore us for our 
contemplation, our pleasure, and our improvement, 
we should make our artificial volume as much in 
accordance with it as possible. What is it, we 
would ask, that is the object of our seeking for a 
knowledge of the parts, productions, and phe- 



NO BLANK IN NATURE. 157 

nomena of the earth ? Is it not that we may the 
more thoroughly and the more rationally enjoy 
the portion of it which comes under our more 
immediate observation?— Is it not that every 
opening of the eye shall be an inlet of knowledge 
and pleasure, that every step which we take upon 
the soil shall be a step in the ways of wisdom, 
and that every object which we examine shall be 
made at once to tell its own tale, and to proclaim 
the wisdom and the goodness of Him whose 
creature it is? 

And it is for the want of this capacity of read- 
ing, as we run the race of life, both over space, 
and during time, that there is any dreary road, 
or any weary hour to afflict us, and embitter our 
lives. Where in creation, we would ask, is the 
blank page? The cultivated field, the barren 
moor, the overshadowing forest, the naked heath, 
the beetling rock, the shifting sand, every thing 
on which the eye can alight, is full of instruction. 
Nay, Sahara itself, the wide and wasted desert, 
is a volume in which, though the characters arc 
different, the language of the Almighty is as forci- 
ble, as in the richest spot under the canopy of 
heaven. It is the same with the succession of 
events; for Nature knows no vacant day — her 
operations are unceasing; and though they vary 
with times and with seasons, as well as with 
places, their variableness is an additional charm, 
an enticement to the study of them, which is ever 
new. The uncultivated mind is, in truth, the 
only blank ; and man is the only idler in creation. 
And we have the proof that it is man's fault in 
the fact that man's punishment is as closely linked 
with it as the light of the morning is with the 
rising of the sun; and we may safely say, that 
14 



158 THE PLEASURE 

nine-tenths of the vice, and more of the misery 
of society arises from the struggle of untutored 
nature to escape from the vacant hour : that hour, 
during which the mind, solely because it is unoc- 
cupied, becomes at once its own tempter and its 
own tormentor. 

But if we all could acquire the power and the 
habit of enjoying with knowledge that which is 
within the range of our observation, and which costs 
us nothing, either in time or in money, we should 
have no leisure to be idle, and no desire to be vicious. 
Imaginethatonehas to cross the most extensive and 
the most dreary common in England, where no 
human habitation is in view ; where there is not 
a trace of human art ; where not a sheep nibbles 
the unproductive surface, and, saving a few little 
tuneless birds, flitting now here, now there, no- 
thing appears to break the monotony of the 
scene. Need we be alone there? — or need our 
thoughts wander either after vice or after vanity ? 
Assuredly not ; for this also is a page of the book 
which is all instruction ; and if we question the 
stunted heath, or the lichen upon the stone, we 
shall find that they have got a tale to tell, and are 
the indexes to the general character of some land, 
to which, in consequence of its position on the 
globe, or the other seas or lands to which it is 
exposed, the economy of Nature has been less 
bountiful than to our country ; and, as we shift 
our ground, and come to the mossy stone, which 
stands high and sheltering, with grassy tufts 
around it, it shall tell us of the benefits of a shel- 
tering elevation, and transport us to the Alps, 
the Himalaya, or the Andes, and show us that 
those lofty and untenanted elevations, with all 
their sterility, and cold, and snows, perform a 



OF KNOWING-. 159 

most important function in Nature's economy, 
by preserving the beauty and the life of those 
regions which lie around their bases. 

We shall not farther pursue this analogy, be- 
cause it must be apparent to every one, that if we 
possess even a little knowledge, keep it about us 
ready for use, and know how to use it, we shall 
be enabled to turn any and every scene into an 
index, not only to all the physical features and 
phenomena of the earth, but to all which has been 
done by man, and for man, upon its surface. 
Could we all arrive at this, it is impossible for 
those who have not entered upon the journey 
toward it to know how delightful we should find 
the world, and how little our peace would be 
disturbed, and our enjoyment interrupted, by 
those little ills and reverses, which are, in the 
very nature of things, inseparable from our con- 
dition ; and which, we may add, fall more heavily 
upon those whom we are apt to envy, than on 
those whom we pity. 

This is by no means so difficult of accomplish- 
ment as some may be apt to suppose ; for, on the 
contrary, it is natural to us, and we have to be 
schooled into refraining from it. The child break- 
ing the rattle, in order to learn the cause of the 
noise which it makes, is an instance which has 
often been brought forward ; but it is one which 
is fraught with the most important instruction ; 
for in that attempt of the child, there is evinced 
the rudiment of that desire of knowledge which 
would raise the man high and honourable in 
acquirements, if, for the sake of a few pence, we 
did not break the desire of knowledge for the 
purpose of saving the rattle. Connexion, relation 
between object and object in place, and event and 



160 ACTION 

event in succession, is the grand matter, all which 
deserves the name of knowledge, indeed ; and 
therefore it is to this our attention should be 
constantly directed. The individual facts may 
be the rods which compose the bundle, but it is 
their relations to each other which form the band, 
and give to the bundle the strength of unity. 
This is needful upon all subjects, and is especially 
needful upon a subject embracing so many parti- 
culars, and particulars so apparently different 
from each other, as are embraced in even a very 
simple general view of the earth. For this rea- 
son we have noticed them here ; and, having 
done so, we shall briefly advert to the subjects 
enumerated in the title of the section. 

But before we can rightly understand how any 
agent acts in the bringing about of any result, we 
must know what resistance that agent has to 
overcome, for it is a law of nature that there can 
be no action of any kind whatever unless there is 
some resistance to be overcome : the agent must 
no doubt possess energy sufficient for overcoming 
the resistance; but admitting this, it may be 
stated as a general truth, that the intensity of the 
action is in proportion to the strength of the 
resistance, and when we consider that all natural 
action, even though the agents of it are what we 
call second causes, is performed under the direc- 
tion, or in strict accordance with the law of the 
Great First Cause, we must be convinced that 
the value of the natural action will always be in 
exact proportion to the resistance which is offered 
to the performance of it. 

The general resistance to all action on the 
earth's surface, whether of agents external of that 
surface, or of the different parts of which it is 



AND RESISTANCE. 161 

composed, is gravitation. As the earth taken as 
a whole is exactly balanced by its own motion on 
the one hand, and its gravitation towards the sun 
on the other, so every piece and particle of mat- 
ter of which the earth is composed is retained in 
its relative position by its gravitation towards the 
earth, and the earth is so much larger than any 
piece of matter which we could imagine to be 
moved on its surface, by any power of motion 
with which we are acquainted, that, if left to 
gravitation alone, every piece and every particle 
of matter must have speedily come to its balance, 
and so remained at rest with regard to the earth, 
without ever changing one way or another. This 
general resistance has, of course, to be overcome 
before there can be any change, that is, any result 
of action. 

Again, all the inorganic parts of the earth, that 
is, all substances, whether solid, liquid, or air, 
(for the same substance may be in either of these 
three states, according to circumstances,) which 
is not part of a plant or animal, the result of ve- 
getable or of animal growth, is held together by 
a species of attraction, or tendency of the parts 
towards each other, which is different from gra- 
vitation, but which acts on the small scale, 
something towards the same effect, though not in 
the same manner, as gravitation acts apon the 
great scale. The grand distinction is, that gravi- 
tation belongs equally to all matter, in proportion 
to its quantity, whatever may be its kind, where- 
as the attractions which hold together the smaller 
pieces of matter depend on the kind of matter, 
and not on the quantity. It would be foreign to 
our purpose to enter into the very curious ques- 
tion of what constitutes difference of kind in 
14* 



162 ATTRACTION 

matter, and though we had room for it, it would 
lead us away from our general subject, and not 
be very instructive, because it is a subject the 
foundation of which is one of those mysteries 
which is coeval with creation itself, and therefore 
beyond the keenest scrutiny of man. We have 
to believe, however, that if all dead matter were 
placed in peculiar circumstances, it might, by 
means of powers or qualities which God has 
implanted in it or endowed it with, separate into 
parts which would, in like parts found in different 
compounds as now existing, arrange itself into 
crystals of some sort or other, every separate one 
obe} 7 ing a definite law ; and when we actually 
examine even the smallest grains of dust, which 
are the dust of the earth as dead matter, and not 
the remains of anything which has once grown 
or been alive, we find that it is composed of little 
crystals, and that all rocks are composed of simi- 
lar materials, though in some the particles are so 
very minute that we cannot examine them at all 
by the naked eye, or perfectly by even the most 
powerful microscope. 

All these minor attractions, as we may call 
them, are resistances which the agents that pro- 
duce changes on the earth's surface have over- 
come, and there is even more than this. It is 
doubtful whether there is any action without 
liquidity, and it is certain that there can be little 
or no living action, either of plant or of animal, 
without the presence of air, not of the mere 
gaseous fluid of the atmosphere, which we usually 
mean when we speak of the air, but of other sub- 
stances in a state of gas, either singly or in com- 
bination. Thus, for instance, a man could not 
live for many minutes, or be comfortable for more 



OF AGGREGATION. 163 

than a few seconds, if there were not a quantity 
of the very same matter of which diamond is 
composed removed from the substance of his body 
in the state of gas, and mixed with one of the 
component parts of atmospheric air. So also no 
plant could be healthy without giving out a por- 
tion of the same substance in the same state ; and 
as the bodies of men and the substances of plants 
contain a considerable proportion of this same 
matter of diamond, there must be some means by 
which it is received into both, and received in 
greater quantity than is necessary. Hence, in 
carrying on the operations at the earth's surface 
there must be in the agents a power of melting 
solids into liquids, and of converting both solids 
and liquids into gases. Farther, as it is ne- 
cessary that the substances so melted, or so turned 
into gas, should, under other circumstances, 
return to the solid state, either in the same 
combinations as before or of different ones, it 
becomes necessary that the agents w T hich melt 
the solids or convert the substances into gas, 
should not destroy the tendency which the mat- 
ter of those substances has, in each, to resume 
the more compact forms, or, if circumstances 
require it, to exert the attractions of the particles 
to their utmost extent, and form crystals. 

Here we see how very simple, yet how beau- 
tiful, the foundations are upon which all those 
varied substances which compose and ornament 
the earth are maintained amid all their changes. 
We may remark also that there is a wonderful 
similarity between the means by which our sub- 
lunary system is kept up amid all its changes, and 
those by which the system of the heavens is sus- 
tained in all the motions and changes of position, 



164 ACTION OP 

distance, and mutual influence of the mighty vol- 
umes of matter of which that stupendous system 
is composed. In the system of the heavens there 
is one principle of gravitation which retains the 
whole of the circulating bodies, planet, satellite, 
and comet, in their orbits, and there is one power 
arising from motion of those bodies which keeps 
them outward to the circumference of the orbit 
with an intensity which exactly balances the force 
with which the attraction of the sun draws them 
toward that luminary; and though, in an elliptic 
orbit, these forces alternately get the better of 
each other, the one which is overcome is not in 
the least destroyed, but retains its elasticity and 
vigour, and re-acts, and overcomes the other in 
its turn. 

Just so in what goes on upon the surface of the 
earth — though the subjects and the phenomena 
are more numerous, there is one law to them all ; 
and here also the opposing forces alternately get 
the better of each other ; and by this means, while 
all the action and all the variation of the system 
is kept up, the powers with which substances are 
endowed are never destroyed. 

General gravitation, as preserving the form of 
the earth and retaining the aggregate of its mate- 
rials in their places, and those particular tenden- 
cies to unite and solidify and crystalize, of which 
we have taken some notice, may be regarded as 
the passive powers in the economy of the earth ; 
and we have the grand active power or agent in 
the sun, in the same manner as in the system of 
the heavens; but to whatever change any one 
particular matter may be subjected, or through 
how many compounds soever it may pass, we 
cannot even suppose that it for one moment loses 



THE SUN. 165 

that principle of solidifying or crystalizing which 
characterizes it as an individual piece of matter 
as perfectly as matter generally is characterized 
by the position of gravitation or weight; and as 
we cannot regard gravitation as an existence apart 
from matter, but merely as a phenomenon of that 
which gravitates, so we cannot regard the ten- 
dency to solidity or crystalize as an existence, but 
merely as a phenomenon of that in which, under 
circumstances favourable to it, it is displayed. It 
is a beautiful part of the system that that same sun 
which retains the planets in their orbits should be 
the grand agent in all the phenomena on their 
surfaces ; for though we know only the earth of 
our own knowledge, we have no reason to sup- 
pose that our earth should be the favoured planet 
and an exception to the law by which all the 
others are regulated. In the meantime, however, 
we are not called upon to examine the uniformity 
of the system to which our earth belongs, but 
merely to notice the agency which keeps up 
growth and life upon its surface ; and that agency 
is, without doubt, the influence of the solar beams, 
which at all times fall upon one half of the earth, 
the centre of which is the point at which the 
radius vector, or imaginary line joining the centre 
of the sun and earth, meets the earth's surface, 
and this point, and consequently the illuminated 
hemisphere of which it is the centre, shifts with 
the motions of the earth, both rotatory and orbital, 
the former producing day and night, and the latter 
changes of season. 

When we say that the rays of the sun fall upon 
the earth, we must be careful that we understand 
what we say, because our common meaning of 



166 PRINCIPLE 

the word "fall" is the descent of matter by gravi- 
tation. 

Now, though the emanation which we call the 
rays or beams of the sun does come to the earth, 
and also goes to every other body in the system 
from that luminary, and though we have the 
means of calculating the rate at which it moves, 
yet we are not warranted in saying that any thing 
comes, that the sun is in the least degree exhaust- 
ed, or the matter in the bodies which it illuminates 
increased one single particle by this action of the 
sun upon them. 

The beams of the sun have several different 
effects ; they heat, they illuminate, they produce 
and destroy colour, and they promote various 
compositions and decompositions, to which it is 
not necessary to attend in order to understand 
their general effects upon the earth. But whether 
we regard the sun-beams as heat, as light, as af- 
fecting the colours, or as affecting the composition 
of bodies, we know nothing of the separate exist- 
ence of a sun-beam. It produces no heat, unless 
in something heated ; nor light, unless in some- 
thing illuminated ; and, in short, no effect what- 
ever, unless there is some substance in which and 
in which alone that effect can become apparent. 
Thus when we speak of the passage or the influ- 
ence of sun-beams, we must not suppose that we 
are speaking of anything which is in itself mate- 
rial, but rather of a kind of action, the power of 
performing which, or, which is the same thing, 
of making the effect of which visible in that which 
is acted upon, belongs to the luminous body. 

Nor must we suppose that there is anything 
peculiarly mysterious in the fact of our having no 
evidence and no ground whatever for supposing 



OF GROWTH. 167 

that the sun-beams are substances of any kind, 
that is, that they are matter, however fine and 
delicate, which might be contained in a vessel, 
and, if accumulated in sufficient quantity, weighed 
in a scale ; for whenever we advance a single step 
beyond the consideration of matter as existing 
lifeless and at rest, and mix up with it the notion 
of any kind of action, how simple or how small 
soever, w T e come to exactly the same perplexity. 
Thus that gravitation which retains the earth in 
its orbit, and gives stability in all its parts, cannot 
be considered as being matter, that is, as capable 
of any existence apart from that which gravitates. 
The motion of the planets in their orbits, by which 
their several gravitations toward the sun are bal- 
anced, is not, in any sense of the word, matter. 
Those minor attractions upon which, as we have 
mentioned, the forms and the qualities of any 
substances depend are not matter. The growth 
of plants, that by means of which they are evolved 
from seeds, rise up in stems in opposition to the 
gravitation of matter, put forth leaves, expand 
blossoms, and ripen seeds which contain the germs 
of new generations, but always of plants of the 
same species, is not matter. The life of animals, 
the power of motion, the will by which that mo- 
tion can in many, indeed in most instances, be 
performed or suspended, is not matter. And at- 
tend to what we will, if we find a single atom of 
matter in any other state than that of absolute 
and unchangeable rest, there is always something 
in supplement to the mere matter which would 
tell in the scale of a balance ; and therefore those 
causes of motion, though in the abstract not ob- 
jects of our senses, and therefore not at all con- 
ceivable by us as separate existences, are as fa- 



168 THE MATERIAL 

miliar to us as that matter, all the phenomena of 
which appear to depend upon them. Nor is it 
consistent with our general experience that, those 
viewless agencies which have not in themselves 
matter should act without any intervening mate- 
rial connexion. The earth requires no chain to 
bind it to the central sun, the stone requires no 
string where it may be pulled toward the ground, 
the hills are not anchored to their places by ca- 
bles and grappling irons, the plant does not draw 
its nourishment towards itself by means of mate- 
rial cords, and there is no matter of connexion 
between the prey and the predatory animal, when 
the hound courses the hare, or the falcon cleaves 
the sky in pursuit of a bird. Now, as that which 
really constitutes the action in all these cases is 
not matter itself, and acts without any material 
connexion, it is in perfect accordance with the 
unity of the system, the one law given by the one 
Creator to the one creation, that whatever influ- 
ence the sun of a system exerts upon the other 
bodies of that system, in addition to the retaining 
of them in their orbits by superior gravitation, 
should, like that gravitation, be action, and not 
matter ; and unless we admitted the original crea- 
tion of the one as well as of the other, our notions 
of what God has made, as well as God himself, 
would be vain and imperfect. And when we 
regard this action as being as essential to what 
we observe in the world as the matter on which 
it acts, we can no more imagine the destruction 
of it than we can imagine the annihilation of 
matter, except by the same power which called 
it into existence to perform the purposes of His 
will. 

Nor must we either wonder at this, or con- 



SYSTEM. 169 

found this action of matter with anything like 
mind, — like that immortal spirit in man which 
has the hope of immortality in it, — for there is 
a distinction between them which, though some- 
times overlooked, is plain enough, and at the same 
time both necessary and desirable to be known. 

The action of matter, on what scale or by what 
creature soever it may be exerted, performs its 
function without plan and without knowledge 
on its part ; and though not a tittle of it can be lost 
to the whole creation, there is no identity and 
therefore permanence in it as relates to any one 
instance of an individual thing or combination of 
things, in which the effects of it may be displayed. 
When a stone 'falls to the earth and there remains, 
it renders up to the mass of the earth the motion 
which it had acquired during its fall, and that 
motion ceases to have any separate existence, nor 
can it be again revived as the same identical ac- 
tion ; so also when a tree withers or an animal 
dies, the growth of the tree and the life of the 
animal are rendered up, never again to be revived 
as the same identical actions, in the very same 
manner as the substance of the tree and the body 
of the animal are, as matter, given up to the dust, 
as soon as an opposite kind of action, the action 
of decomposition, as belonging to dead matter, 
has destroyed their organic structure. And we 
may add, that if the purpose of the Almighty 
with regard to a planet, or even to a sun with all 
its attendant system, should be accomplished, and 
the period for which He had ordained it to last 
at an end, that planet or that sun and system 
would no more return in its individual identity ; 
but yet neither its matter nor its motion would 
be lost to the universe, though the eye and the 
15 



170 VELOCITY OF LIGHT, 

telescope of observation might seek for it in vain. 
And this holds of all matter and of all action of 
mere matter, including the human body among 
the rest; for in all that is declared of the resur- 
rection there is allusion to "a neiv body:" — 
"This corruptible shall put on incorruption ; this 
mortal shall put on immortality." "It is sown a 
natural body; it is raised a spiritual body." 

This view of the substance and the action of 
matter is far more important than any detail of a 
single science, or any statement of individual 
facts, however correct and however minute, 
because it is of far more consequence that the 
mind should feel its ground firm under it than 
that it should struggle in quagmires ; and unless 
we see clearly that there has been created an 
action of matter as well as a mere substance of 
matter, and that the varieties of the action impress 
on the substance all the varieties of its appearance, 
and bring about all the changes which it under- 
goes, wercannot have a thorough ground of hope 
in the immortalit}^ of our own spirits, as resting 
upon the judgment of reason, neither can we have 
a due impression of the wonderful power and 
still more wonderful goodness of our Maker. 

Truly this action of matter is a wonderful 
thing; it controls suns and systems, operating 
athwart distances, at the very thought of which 
the fancy turns giddy ; and not only can " not a 
sparrow fall to the ground" without its control, 
but there is not a mote that dances in the sun- 
beam, or a particle, it may be not the millionth 
part of a mote, which is not as much under its 
government as the mightiest mass in creation, — 
aye, the most apparently insignificant event that 
comes round — the opening of a bud, the drooping 



AND OF THOUGHT. 171 

of a leaf, or the nicker of a thistle-down — but 
which belongs as much to the system, and is as 
safe in the administration of the law, as the roll 
of the ocean, or the career of a planet. 

But mighty, and incomprehensible to us, as the 
action of matter is, there is the stamp of mortality 
upon it, in every individual case or form in which 
we can see it displayed. The emanation of the 
sun, which we are to consider the grand cause of 
the greater phenomena of the earth, vast as it is, 
and mighty as is the distance across which it can 
exert its varied and curious influences, falls short 
of the power of the immortal spirit in man. We 
can determine its motion only when we consider 
it as light; because the distance at which we can 
have any knowledge of it as heat, or in any other 
point of view, except as light, is very limited; 
and we may say, that we require the direct con- 
tact of the action of heat with that which is heated, 
and, in many instances, the continuation of that 
contact for a time, before the effect is perceptible. 
In the case of light it is different. The eye, being 
a material organ, of course has a limit, beyond 
which it cannot see ; but the range is greater than 
any length which we can determine ; and we have 
an easy means within that range of finding the 
rate at which the action of light is propagated. 
We can observe the planet Jupiter in two differ- 
ent positions of the earth's orbit ; in the one of 
which we are the whole diameter of the orbit of 
the earth, or about 190,000,000 of miles, nearer 
to Jupiter than in the other. We can also cal- 
culate the time at which the eclipses of Jupiter's 
moons begin and end ; and this we can do, refer- 
ring them to a common centre. Now it is found, 
by actual observation, that when the eclipse is 



172 IMMORTALITY. 

observed from the longer distance, it happens 
about 16 m 26 s later in time, than when it is ob- 
served from the shorter distance. The part of 
the eclipse which is chosen for this purpose is, 
the instant that the moon emerges from the 
shadow of Jupiter; and it is evident, that the 
above mentioned minutes and seconds are the 
time that the light of the satellite requires to 
travel across the earth's orbit ; and if we divide 
the diameter of tbe orbit by the seconds, we find 
that the propagation of light is at the rate of about 
1 92,000 miles per second. We cannot accurately 
observe a much shorter time than the fifth of a 
second, and during that time light advances 38,500 
miles, or rather more than equal to li times round 
the earth. 

This, it will be admitted, is a motion of most 
astonishing rapidity ; but still it is nothing com- 
pared with the motion of thought, which is of 
course the propagation of the action of mind, just 
as that with which we are comparing it is the 
propagation of one display of the action of matter. 
But the mind does not require 16 m , or even 16 s , 
or a measurable fraction of 16 s , to carry its 
thoughts, not across the orbit of the earth merely, 
but round the orbit of every planet in the system, 
and onward to every known star. Now, if this 
is not a proof that mind is something higher, or 
something more pure and ethereal, and therefore 
more absolved from the possibility of destruction, 
than matter in its most gigantic masses, and the 
action of matter in its fleetest career, we know 
not where such a proof of it is to be found ; and 
if in our examination of that grand agency, whose 
effects upon the earth we are about to examine, 
this philosophical establishment of the immate- 



ACTION OF HEAT. 173 

riality, and, by consequence, the immortality of 
mind, would be in itself an ample reward for the 
small trouble which the analysis of the subject 
costs us. Nor is it possible for us to approach 
such subjects without a feeling of the most reve- 
rential, but, at the same time, the most delightful, 
gratitude, that the jewel of immortality is to be 
found in every casket of nature, and that every 
casket may be opened, if we will but use the 
key. 

We are therefore to understand that the action 
of the sun, to which we give the name of sun- 
beams, and which is altogether different from the 
attraction of gravitation of the sun as a mass of 
matter, is the great agent in terrestrial phenomena ; 
and that this agent acts as heat, as light, and in 
various other ways, nor have we any means of 
ascertaining the exact number. 

It is considered as heat that this agency per- 
forms its principal operations on the grand scale ; 
and therefore this is the sense in which we require 
to understand it most fully. Now, the general 
effect of heat, whether we regard it as the heat of 
the sun or as heat from any other source, is to 
counteract the attractions or cohesions of matter, 
by means of which the small parts of which bodies 
are composed are held together ; and though we 
cannot practically arrive at the bottom of the 
scale, or that state of bodies in which we can say 
there is no action of heat, yet we may presume 
that solidity would in all cases be the result of 
the withdrawal of this action to a certain extent ; 
and that, on the other hand, if a sufficient action 
of heat were applied to any substance whatever, 
under proper circumstance, that substance would 
pass into a state of liquid, and afterwards into a 
15* 



174 ACTION 

state of gas; and also that, if we could still con- 
tinue to apply an increased action of heat, this 
gas might be spread to an unlimited extent 
through space, so that no sensation and no instru- 
ment could detect its existence, — that,for instance, 
a solid body not bigger than a pin's head might 
be so operated upon by heat as to be diffused 
equally through the whole of the space occupied 
by the solar system, or through any space how 
large soever. 

But though the action of heat thus changes the 
form and the volume of all bodies, and though 
we cannot imagine any portion of matter capable 
of resisting it, if made to act with sufficient in- 
tensity, yet we are not to understand that heat 
either deprives the matter so acted upon of its 
tendency to gravitate, or of that particular attrac- 
tion of cohesion, when the absence of heat allows 
it to operate, which determines a body to be of 
one kind of matter rather than of another. It is 
true that most of the bodies which we meet with 
in nature, whether organized bodies or not, are 
compounds ; and the action of heat upon them 
very frequently separates the compound, and 
dissipates some of the component parts, while the 
others are left behind ; and as the conclusion to 
which we come with regard to any substance, 
being simple, is not the ultimate conclusion in 
nature, but merely the point beyond which our 
observation and experience cannot be carried, we 
cannot say positively that there is any such thing 
as an absolutely simple portion of matter in ex- 
istence, that is, a portion which could not by 
possibility be resolved into two or more parts, 
differing from each other in their properties. 
When we speak of simple substances we must 



OF HEAT. 175 

always be understood as speaking of them with 
this limitation ; and thus far it is quite sufficient 
for us, because any speculation beyond what we 
know cannot be wisdom, and is very likely to be 
folly. 

Heat acts very differently upon different sub- 
stances, but these modifications of its action are 
matters of detail; and though the applications of 
them are of the greatest use both in the under- 
standing of nature and in the practice of the arts, 
yet it belongs to chemistry, and not to a general 
view of natural action. But we may mention, 
that heat always acts most intensely on that which 
abides its action, or which has not some means of 
defence in the particular form, texture, or colour 
of its surface. A solid is the body most easily 
affected by the action of heat, because it cannot 
escape ; a liquid is less so, because it can escape 
in vapour, though the liquid which passes the 
least readily into vapour can receive the strongest 
impression of the action of heat. It is for this 
reason that boiling oil burns one so much more 
intensely than boiling water. Gases are the most 
difficult to be made sensibly hot, because they 
get away from its action by expanding, and oc- 
cupying a larger space ; or if the heating cause 
is near the surface of the earth, the heated gas 
mounts up in the atmosphere, and gets out of the 
reach of the action of farther heat. 

Substances have the power of reflecting, or 
turning away from their surfaces, the action of 
heat ; and this increases in proportion as the sur- 
face is whiter and more smooth, and diminishes 
in proportion as it is darker in the colour, and 
rougher. 

If the action of heat which is applied to bodies 



176 ACTION OF HEAT. 

is not wholly exerted in loosening their cohesion, 
and increasing their volume, then they are dis- 
posed to give it out to all the surrounding bodies 
in proportion as these are disposed to receive it ; 
and this giving out may be effected by direct 
transmission, if the bodies are in contact, or by 
radiation, if they are at a distance. 

If the heat expands the volume of a body with- 
out effecting any decomposition, the heat may be 
abstracted ; and when this is done the body will 
return to nearly its former volume. This is not 
always the case, but as we do not know what 
bodies are absolutely simple, or whether there be 
any such, we are of course unable to know with 
certainty what part may have been removed, or 
what new part added, in any case of the applica- 
tion of heat. 

The few particulars which we have mentioned 
tend to show that, though heat may be regarded 
as only one agency, the effects of it are varied 
without end ; and that, what with melting, and 
turning into gas, and separating compounds, it 
sets matter free from the trammels of its existing 
attractions and combinations, and thus enables it 
to enter into new ones ; and thus the constant 
succession of destruction and renovation, of ex- 
tinction of life in the old and commencement of 
life in the young, is enabled to be brought about. 
The doctrine of heat is indeed the most interest- 
ing doctrine in the whole study of material nature ; 
and it cannot be otherwise, because heat is the 
grand agency by which results are brought about, 
both in the operations of nature and in the prac- 
tice of the arts ; and, though a result or phenome- 
non also follows the withdrawal of heat, we are 
to consider this matter as a return to the state 



ACTION OF THE SUN. 177 

previous to the action of the heat — just as we 
consider the dissolution of a body after death 
as the return of its material substance to dust. 

Considered as light, the action of the sun is also 
highly interesting; and, as it is in this point of 
view that it displays all nature to our observation, 
it is, perhaps, more fascinating to us than the 
study of heat, though we have no reason to believe 
that its effects are nearly so powerful in the great- 
er operations which are carried on upon the sur- 
face of the earth. That it does produce many 
effects is certain ; as, for instance, it increases the 
quantity of charcoal in plants, and imparts to 
them the greater number of those properties in 
consequence of which they show colour; for 
plants which grow wholly excluded from the 
light are white. But, in the action of the sun 
upon the earth, light and heat, and all the other 
modifications of the agency, are so constantly 
united, and, indeed, in all probability, so identi- 
cally one action, only varied by the objects acted 
on, that we may consider them as acting together, 
and as one simple energy. 

The law which this energy follows is, to ema- 
nate from every point of a body which, like the 
sun, gives out visible light and sensible heat, and 
which for this reason is called a radiant body, 
and to emanate from every point in all directions, 
but always in straight lines. Whether it moves 
at the same rate throughout the whole of its 
journey, or slackens as it proceeds, we have no 
means of ascertaining ; but as, though it is from 
points on the surface only that it can proceed to 
other bodies, yet, like gravitation, it is referable 
to the centre of the radiating body, and therefore 
its intensity at different distances must be inverse- 



178 SEASONAL ACTION 

\y as the squares of those distances, — that is to 
say, at double 1he distance it will have only one- 
fourth of the intensity, at three times the distance 
only one-ninth, and in a similar relation for all 
distances whatever. And, as the emanation pro- 
ceeds in the same way, whether we regard its 
effect as heat, as light, or anything else, we of 
course must consider them all as diminishing in 
the same ratio. But the distances of any two 
points on the earth's surface from the sun differ 
so very much from the mean distance, that it is 
not worth while to take this consideration into 
the account in our estimates of the solar influence 
upon different regions of the globe. 

Though the general effect of the sun-beams, 
and indeed of heat from any other source, be to 
soften, and melt, and expand every substance, 
the parts of which are not separated from each 
other by this operation, yet, when the parts are 
saparated, the result, upon that which remains 
is often consolidation and hardening. Thus, 
when the solar heat drinks up the water with 
which clayey soil is impregnated, by turning 
that water into vapour, the clay becomes indu- 
rated, and, contracting, champs and breaks into 
deep fissures ; and, in like manner, when the heat 
of the sun turns into vapour the moisture of the 
vegetation on field or in forest faster than the 
feeders of the vegetable can supply the waste, 
the herbage is burnt up, and the trees languish 
and drop their leaves, and, if the fervour is of 
sufficient continuation, they wither, and, if nature 
has not adapted them to endure this extremity, 
they die. There are curious provisions in the 
vegetable world for guarding against this destroy- 
ing action of the sun. The plants of the desert 



ON TREES. 179 

generally have their leaves thick in substance, 
and covered with an epidermis, or outer skin, 
which is smooth, to turn away the influence of 
the sun by reflection, and at the same time re- 
markably tough, and free from any pore. But 
there are many of the more arid regions which 
still have moisture enough during one part of the 
year for the growth of shrubs ; and many of those 
shrubs shed their leaves, not by withering, but by 
heeling off, as our desiduous trees do in the au- 
tumn, and then they go into a state of repose 
during the excessive heat, not dissimilar to that 
into which our trees and shrubs pass during the 
winter. 

On the trees which grow on the intermediate 
lands in warm climates, and which are not only 
evergreen, but, with short pauses, overgrowing, 
the leaves have, generally speaking, the same 
smooth and firm epidermis as the plants of the 
desert ; and any one may observe that all ever- 
greens which bear the rigour of winter with us 
without shedding their leaves, have those leaves 
much more firm in their texture and smooth in 
their surface than trees which shed their leaves 
in the winter; nay, so close is this connexion be- 
tween the firmness and smoothness of the leaf, 
and the power of endurance in the plant, that 
among our deciduous trees the delicate leaf is 
always the first to fall, and the leaves which have 
smooth surfaces remain longer on the tree than 
those which have not. The mulberry and the 
beech are perhaps extreme instances in this coun- 
try ; the leaf of the mulberry is delicate, and its 
surface is not smooth, and mulberry leaves drop 
at the very first frost, without having previously 
shown any signs of decay, so that they may be 



180 ACTION OF 

gathered from the ground on the morning of one 
day as green and perfect as they were on the 
tree the day before. The leaves of the beech, on 
the other hand, are firm and smooth after they 
come to maturity, so that they are less eaten by 
insects than the leaves of most trees, and, instead 
of dropping at the first frost, they have a very 
gradual decay, and in many situations clothe the 
tree with a russet mantle, which lasts during the 
greater part of winter. The action of heat upon 
the individual productions of nature is, however, 
a matter of many details, and we have thrown 
out these hints merely in order to show that it is 
worthy of being studied. Having done so, we 
shall mention the instruments by means of which 
the action of the sun is distributed over the earth, 
and by means of which the intercourse of nature 
is carried on between one place and another. 

The grand instruments by which the action of 
the sun is distributed over the earth, and in so 
far equalized in different regions, are the air and 
the water ; and therefore it is necessary to have 
some knowledge of them before we can rightly 
understand the economy of the earth. 

The air is the grand messenger. It every- 
where invests the earth to an indefinite height, 
but a height far greater than the summit of the 
most lofty mountains, and it becomes rarer, or 
contains less matter in an equal bulk, as we ascend 
above the surface. Though we must reserve the 
explanation of the principles on which it acts, 
and also those phenomena of which it is more 
immediately the instrument, to our volume on 
the air, yet it would be impossible to render 
the present subject intelligible without some al- 
lusion to its properties, and therefore we must 



THE AIR. 181 

state them, but we shall do it very briefly, and 
without going into the investigations from which 
the properties are deduced. In all our rational 
and useful inquiries into nature we labour under 
this difficulty, — that it is impossible to be syste- 
matic, — to begin with some one element which 
we can clearly define, and proceed gradually to 
the others. We require the whole at once, or 
else we tie ourselves down to the individual 
points, which, taken singly, have butlittle interest, 
and thus our knowledge of them is imperfect, 
and comparatively useless in so far as it goes, 
from want of the connexion. For these reasons, 
when we would so treat the subject as to be popu- 
larly interesting and popularly useful, we must 
sacrifice the regularity of system, and be con- 
tented with a little real knowledge divested of 
all the appearance, and deprived of all the honour, 
of wisdom and learning. 

The air, and all other substances which are in 
a state of gas, may be considered as having the 
attraction of cohesion between their particles so 
perfectly subdued and neutralized, that they are 
instantly obedient to the operation of the slight- 
est force that can be applied to them. On this 
account they have sometimes been called elastic 
fluids ; that is, fluids which have a spring ; but as 
there is perhaps no substance which has not some 
elasticity or springiness, and as there is no sub- 
stance in which that property is absolutely per- 
fect, the name is not a very happy one, as it is 
apt to mislead those who are endeavouring to un- 
derstand the reality. The air is, however, a very 
springy substance, the most obedient spring with 
which we are acquainted ; so much so that it may 
be always said, in all cases and in every situation, 
16 



1S2 ACTION OF 

to be constantly at the top of its bent. It is the 
cohesion of the air which is neutralized much 
more than its gravitation, for the latter is a pro- 
perty which is constant to the quantity of matter, 
and is no farther affected by heat or any other 
cause than that cause alters the specific gravity, 
or quantity of matter, in a given space ; but the 
cohesion of air is so far subdued that, though not 
destroyed, it is converted into or changed for a 
principle of repulsion, as between particle and 
particle, a tendency to occupy more space if not 
restrained by some cause. The gravitation or 
weight of the mass of air counteracts it in this 
way, and keeps it in its position over the surface 
of the land and sea, but at the same time leaves 
it a perfect freedom of motion in obedience to 
any impulse that it may receive : and the decrease 
of density as we ascend is the means of an up- 
ward or a downward motion, according to circum- 
stances. If air were confined in a close vessel, 
and sufficient heat applied, it is probable that it 
could be brought to a degree of temperature much 
higher than any furnace with which we are ac- 
quainted ; but when it is in its free state, it ex- 
pands whenever heat is applied to it, and if it can 
expand without any opposition, it does not get 
sensibly warmer. Any opposition which it can 
meet with to expanding in the open atmosphere 
can be only the weight of the air around it and 
over it ; and in proportion as this is less, the sen- 
sible effect of heat upon the air must be less. 
But the air is less dense as we ascend above the 
mean level of the earth's surface, and therefore 
as we ascend above that surface the air must be 
colder, and also more uniform in its temperature 
than it is lower down j farther, if the air is enclosed 



THE AIR. 183 

between lofty elevations of the ground, these 
must co-operate with the gravitation in rendering 
the expansion more difficult, and therefore the 
same action of heat must produce more sensible 
heat in confined valleys than on open expanses, 
arid, more generally speaking, on the surface of 
the land than on that of the sea. But if air ex- 
pands by the application of heat, and in this ex- 
pansion has to work against gravitation, which is 
a permanent and indestructible principle ; and as 
the two are, as we have said, always exactly bal- 
anced; the withdrawal of the action of heat must 
enable the gravitation to re-act, and produce a 
compression, condensation, and increase of weight 
proportional to the heat withdrawn. Farther, as 
the spring of the air extends round the whole 
globe, and is everywhere equally obedient to 
gravitation, in proportion to its density, there 
must be a constant tendency in the denser portions 
to descend to the surface, as there is in the rarer 
ones to ascend from it; also, when any portion 
has been heated for a time, and thereby expanded, 
if the heat is withdrawn, the surrounding portions 
must press in upon it, and the gravitation must 
bring it downward until an equal equilibrium 
is restored. Thus, though every particle of the 
air is always balanced, and we cannot call it un- 
stable, it is the most moveable of material things, 
and its mobility fits it admirably for being the 
general messenger of nature upon the earth. 
These hints as to the general nature of air must 
suffice in the meantime, and we have endeavoured 
to make them such as any one can verify by ac- 
tual observation. 

The next point of inquiry is, "what does this 
general messenger of nature carry ?" The an- 



1S4 ACTION OF THE AIR 

swer to this is, it carries heat, and it carries moist- 
ure, but chiefly the latter ; and in this respect it 
may be said to bring drink for all the children of 
nature that inhabit the land. It does even more 
than this, for it alters the form of surface in the 
seas, and causes motions or currents in the water 
of them. It does this by the variable pressure of 
its gravitation ; and though the extent may not 
be great over surfaces of moderate extent, yet 
there is no doubt that it is considerable on the 
wide oceans. The air presses, upon an average, 
with the weight of about fifteen pounds upon 
every square inch of the surface, whether of the 
land or the sea; and it is subject to variations of 
pressure, varying sometimes as much as a fifth 
part of this quantity, or about three pounds on the 
inch. Now, if we suppose that a pressure of this 
kind comes upon the sea in the southern hemi- 
sphere, where the surface is so extensive, while 
there is no such pressure on the sea in the north- 
ern, it is easy to perceive that the ocean waters 
will get an impulse northwards; and, generally 
speaking, if there is more pressure of the air 
upon one part of the surface of water than upon 
another, the water will be depressed where there 
is most weight upon it, and elevated where there 
is least. 

The air is supplied from the surface of water, 
and of every thing humid, with that moisture 
which it carries. This is taken up by the air in 
the very curious process of evaporation, which is 
much too intricate for being explained here, but 
which any one will readily understand, at least in 
its effects, who observes that, even though the 
sun is not shining, the surface of the ground dries 
on a rainless day ; and that if a warm surface, 



ON WATER. 185 

such as that of a dry road or a pavement, is wa- 
tered, and left to dry, it produces an agreeable 
coolness, and gives motion to a refreshing current 
of the air. Or the same thing may be personally 
felt ; for if in a very dry day the hands are dipped 
in water, and then held up with the fingers ex- 
panded, they will not only become agreeably cool, 
out if the operation is repeated often enough, 
they will feel as chilly, under exposure to the 
summer sun, as they would do in the winter 
air. 

This evaporation invariably produces cold, so 
that a portion of the action of heat is required in 
order to reduce the water into those small parti- 
cles in which it ascends in the air, is held sup- 
ported by that substance, and carried from one 
region to another. 

The different degrees of heat to which it is ex- 
posed have also some effects upon the density of 
water, but trees are so small that, in a cursory 
view of the phenomena of the earth's surface, we 
need hardly take them into account. 

The reader cannot have failed to remark the 
very different effects which the grand agent in 
terrestrial phenomena, the beams of the sun, 
considered as heat, produce on the air and on the 
water. They expand the air without removing 
any part of its substance, and thus set it in motion 
all over the earth, while they enable the air, as a 
messenger, to take up such a burden of water as 
is necessary for the general purposes of the earth's 
economy. 

It is impossible to view the three subjects on 

which we have remarked in this section, either 

in their own nature or in their connexion and 

their adaptation with each other, without being 

16* 



186 MOTION AND 

struck with the astonishing display of wisdom 
which they offer to our contemplation ; and when 
we consider the range of the scale upon which 
they act, the extreme vastness on the one hand, 
and the incomprehensible minuteness on the other, 
and yet that in all the countless millions of their 
results, whether magnificent or minute, there is 
equal perfection in the attainment of the intended 
purpose, we cannot refrain from considering this 
as the grand demonstration of the greatness and 
the goodness of the Creator, the wonder in short 
of the material creation. The agent, the influence 
of the sun, comes on the average from the distance 
of 95,000,000 of miles, and comes at the rate of 
192,000 miles in a second, and it comes in such 
a way as to tell not only upon every point of 
the earth's surface, and every drop of the ocean, 
but upon every particle of the atmosphere, even 
at those vast elevations at which these particles 
are so thinly scattered as that they could not sup- 
port the down of the lightest feather, no, not the 
thin air which we meet with on the summits of 
the mountains, or the more attenuated gas with 
which we fill balloons that carry men and their 
apparatus more than mountains high. This all- 
pervading energy, which works for good to the 
whole earth, notwithstanding its immense velo- 
city, does not injure a single thing — does not 
bend a fibre or break a cobweb. In this there 
is a proof altogether irresistible, that this influ- 
ence of the sun cannot be matter, in our sense of 
the word. The atmospheric air is, in all proba- 
bility, divided, down to the ultimate particle, and 
therefore it contains in its substance no single 
piece of matter which can strike any mensurable 
portion of the surface of any body. But when 



VELOCITY OF LIGHT. 187 

the air is put in motion, only to the velocity of 
our swiftest birds, which we can easily see for 
considerable distances on their flight, that is, when 
it moves at about one hundred miles in the hour, 
it forms what we call a hurricane, which uproots 
the forests, levels the habitations of men with the 
ground, and sweeps the crop, and even the soil 
in which it is rooted, into the sea. But the velo- 
city of the hurricane is a mere nothing compared 
with that of the solar action, which is 1,920 times 
as fast in a minute as the hurricane sweeps in an 
hour. At this rate the solar action moves very 
nearly, 7,000,000 of miles in the time that the 
hurricane moves one mile. But moving bodies 
strike against surfaces, and therefore the forces 
with which they strike are as the squares of ve- 
locities, and therefore if whatwecall the sun-beams 
were composed of matter as dense as the atmo- 
sphere, they would strike the earth, over thewhole 
hemisphere on which they fall, with a force equal 
to that of 49,000,000,000,000 (forty-nine billions) 
of hurricanes, which is utterly above our com- 
prehension, but which certainly would suffice in 
one moment to turn the earth into invisible va- 
pour. But the sun-beams produce no injurious 
effect, and therefore it is impossible to conceive 
that they can consist of anything but mere action, 
perceptible only in its effects. It is farther aston- 
ishing that this action should be the means by 
which every living and growing thing is called 
into being, the pencil which paints Nature in all 
her varied hues, the odour which perfumes the 
flowers, the aroma which gives raciness to the 
fruits, and the interpreter to the human eye of 
all the wonders of its working. Nor is it less a 
marvel that this little organ can question the 



18S NATURAL THEOLOGY. 

fleeting beam, and make it render up that know- 
ledge which it carries onward on wings which 
are swift beyond all human comprehension. 

It is in these views of natural action that we 
have the most splendid displays of the Creator ; 
and it is somewhat singular, that those who have 
written expressly on what is called natural the- 
ology, should have neglected or omitted this most 
beautiful, most striking, and most convincing part 
of the subject. Lord Brougham, in the very 
delightful discourse which he has recently pub- 
lished, as introductory to a new edition, with 
annotations, of Paley 's " Natural Theology," well 
remarks, that that very popular, but not very 
profound, author, has strangely omitted all allusion 
to mind in his treatise; and his lordship might 
have added, that not only in Paley, but in those 
abler authors of whom Paley is little else than 
the copyist, the only part of the subject which 
evinces Almighty power is almost or altogether 
neglected, and that the whole of the magnificent 
system of creation is brought down to the stand- 
ard of common mechanics. By this means the 
subject is deprived of the greater part of its in- 
terest, and the Creator of the greater part of the 
glory which cannot fail to be ascribed to Him by 
every one who duly understands the working of 
that wonderful system of which He is the Author. 
Indeed, as the God of Nature is the living God, 
it follows by necessary consequence that he must 
be most powerfully and most clearly displayed, 
not merely in living nature, but in that which 
constitutes nature's life. 



189 



SECTION IX. 

MODIFICATION OP THE SUn's ACTION, BY THE 
FIGURE OF THE EARTH. 

Those circumstances which occasion the dif- 
ferences between the several regions of the world, 
in respect of their vegetable productions, their 
animal inhabitants, and their adaptation as abodes 
for man, are often summed up in the general 
name, climate; but as that word was originally 
applied to positions in latitude, or differences of 
length in the longest day only, and as this is only 
one of the elements upon which the real climate, 
the average temperature, the fertility, and the 
characters of the seasons depend ; and further, as 
there are great differences of climate in the same 
latitude of the two hemispheres, and also at dif- 
ferent parts of the same hemisphere, it would be 
better to treat separately the chief causes upon 
which these depend, and then to see how the 
whole apply to the several countries. 

The first to be noticed, because the simplest, is 
that which we have set down as the title of this 
section — the modification of solar action by the 
earth's figure ; and on the consideration of this 
there is no necessity for any allusion either to the 
daily or the annual motion of the earth. 

From the earth being nearly globular, the sun 
being a much larger globe, and the rays of light 
and heat coming in all directions from every 
point of the sun, we may assume, that the whole 
beam of the sun which the earth intercepts, and 



190 ESTIMATE OF 

which is exactl)?- equal to a section of the earth, 
on the plane of a great circle, the pole of which 
is the point of the earth's surface, met by the 
line joining the centres of the two bodies, comes 
to the earth as in lines parallel to each other; 
that is, that the whole of this cylindrical beam, 
8000 miles in diameter, which the earth intercepts, 
is of equal intensity, so that if it acted upon a 
plane surface, instead of the convex hemisphere 
of the earth, it would illuminate and warm the 
whole of that plane surfaee equally. But this 
beam of light and heat is intercepted by the con- 
vex hemisphere, on the centre of which it falls 
perpendicularly, and beyond the boundaries of 
which it passes in tangents to the circumference, 
without at all acting on the surface. The first 
point to be ascertained is, the power which the 
beam itself has to produce effects on the different 
parts of the hemisphere on which it falls. 

If the whole surface of the hemisphere were of 
uniform matter and texture, so that the solar action 
would be equal, and all points of it equally ex- 
posed to that action, then the effect upon every 
point would be matter of very simple geometrical 
investigation, upon the very simple principle, 
that the same power, acting in the same manner, 
upon surfaces exactly similar, must have exactly 
the same effect upon each. 

In the centre of the illuminated hemispheres 
the effect must be the greatest possible ; and what 
it is, is matter of observation, by means of any 
instrument which can be employed as a thermo- 
meter, or measurer, of heat. We cannot, of 
course, get at the exact mathematical degree of 
heat which would be found at the maximum point, 
or that where the sun is vertical, in the supposed 



191 

case of the surface of the hemisphere being per- 
fectly uniform, and there being no external 
substance to affect the influence of the sun. The 
reasons why we cannot do this are very obvious: 
we have no hemisphere of uniform surface, and 
we always have the atmosphere ready to convey 
heat from the places which are warmer, by mount- 
ing up with it from the surface, and bearing it oft' 
to colder places. 

As little can we have a thermometer which we 
can be sure will indicate the proportions of the 
solar action, in different places, with equal accu- 
racy. Our thermometer usually consists of a 
quantity of some fluid, as of spirits of wine, or 
mercury, enclosed in a glass case, consisting of a 
ball and stem, or tube, with the air expelled and 
excluded from the vacant part. The degree of 
heat, whether of the sun, or of anything else, 
which such an instrument measures, is only the 
expansion of the fluid which it contains; and, 
therefore, it can tell us nothing further than the 
effect of heat in expanding that particular fluid. 
But even this is something ; for though we do 
not get the absolute heat in any one case, we get 
its relations in different cases, which answers 
very nearly the same purpose. This does well 
enough in practice, where we have to find the 
joint effect of all the causes upon which the de- 
gree of heat, or, as we call it, the temperature, 
depends ; yet we cannot apply it to the simple 
case of a hemisphere of uniform surface and uni- 
form susceptibility to the action of the sun, which 
is the element of climate now more immediately 
under consideration. 

The sun's action is a maximum, or the greatest 
possible, at the point where the sun is vertical j 



192 THEORETIC DIFFERENCES. 

that is, at the centre of the illuminated hemi- 
sphere ; and it becomes less as we recede from 
this point, in proportion as the surface turns away 
from this ; that is, it is in the proportion of the co- 
sines of the angular distances from the centre of the 
hemisphere, — the radius of the earth, which, in 
the case of the earth's convex surface, is the co- 
sine of a quadrant, or 90°, being the expression 
for the maximum effect, that is, for the effect when 
the sun is vertical. It is of little use to state 
what the rate of this decrease of solar action, from 
the centre to the circumference, upon the hypo- 
thesis of uniform surface, is ; inasmuch as there 
is nothing answering to it in what we can ob- 
serve ; but as it is true in theory, and as the 
deviations from it in reality arise from the nature 
of the varied surface of the earth, from the 
motions of the earth, and from the effects of the 
atmosphere, it may not be amiss to state, in ap- 
proximate terms, the proportional action for every 
five degrees. 

If we call the whole as maximum action, at the 
point where the sun is vertical, 1000, we have 
the following proportional numbers for the other 
parts of the hemisphere : at 5°, or 350 miles from 
the centre of illumination, 996; at 10°, or 700 
miles, 984; at 18°, or 1050 miles, 965; at 20°, 
or 1400 miles, 939 ; at 25°, or 1750 miles, 906 ; 
at 30°, or 2100 miles, 866 ; at 35°, or 2450 miles, 
819 ; at 40°, or 2800 miles, 766 ; at 45°, or 3150 
miles, (the middle distance,) 707; at 50°, or 
3500 miles, 642 ; at 55°, or 3850 miles, 573 ; at 
60°, or 4200 miles, 500, or one-half the maximum ; 
at 65°, or 4530 miles, 422 ; at 70°, or 4900 miles, 
342 ; at 75°, or 5250 miles, 258 ; at 80°, or 5600 
miles, 173; at 85°, or 5950 miles, 87; and at 90°, 



OF TEMPERATURE. 193 

or 6300 miles, (the extremity of the hemi- 
sphere,) 0. 

In order to see how slowly the action decreases 
near the centre of the illuminated hemisphere, 
and how rapidly near the boundary or termina- 
tion, it may not be amiss to bring these numbers 
together, and to state the progressive difference 
between every successive- 5 G , and the total dif- 
ference between each and the maximum. 

Degrees from .... 0° 5° 10° 15° 20° 25° 

Proportions 1000 996 984 965 939 906 

Progressive difference 4 12 19 26 33 

Difference from max. 4 16 35 61 94 

Decrees • 30° 35° 40° 45° 50° 55° 

Proportions 866 819 766 707 644 573 

-Progressive difference 40 47 53 59 65 69 

Difference from max. 134 181 234 293 358 427 

Decrees 60° 65° 70° 75° 80° 85° 

Proportions. • • • • 500 422 342 258 173 87 

Progressive difference 73 78 80 84 85 86 

Difference from max. 500 578 658 742 827 923 

At 90° prop. = ^prog. diff. = 77; diff. from max. = 1000. 

These numbers are but rude approximations, 
but they arc sufficient to show the principle; and 
it is not necessary to go into the minutiae, because, 
as we have said, there is nothing in actual obser- 
vation to correspond with this theory. Still as 
this enters as one clement into what we actually 
observe, it is necessary to understand the princi- 
ple. Were it not for the atmosphere, the currents 
of the ocean, the motions of the earth, and the 
different ways in which the sun acts upon different 
kinds and shapes of surfaces, the theory as above 
stated would be found to agree with observation ; 
and thus wo are led to inquire into the causes 
17 



194 ADVANTAGES OP 

why the actually-observed facts are different from 
the results of the calculation. 

At 10° from the point where the sun is vertical, 
the diminution of the sun's influence is less than 
l-60th ; at 20° it is less than 1-1 6th ; at 30° it is 
less than l-7th ; at 40° it is less than l-4th ; at 
50° it is more than one-third ; at 60° it is exactly 
one-half; at 70° it is more than 6-10ths; at 80° 
it is 17-20thsj and at 90° it is the whole. 

The half temperature is thus at 60° while the 
half distance is at 45°, the difference of which is 
15°, or about 1050 miles all the way round ; and 
this is the advantage in effect of solar influence 
upon the earth, which it derives in consequence 
of its spherical figure. This advantage is not lost 
in consequence of any of the circumstances which 
modify the action of the sun, because those 
modifications affect the whole temperature, and 
consequently do not affect this element of it any 
more or in any way different from the others. 

Thisisanother remarkable instance of advantage 
arising from the very simplest and most general 
and elementary principle in nature — the gravita- 
tion of matter. It is in consequence of this gra- 
vitation that all the heavenly bodies, which are 
composed of matter having any degree of density, 
have assumed the spherical form ; and this form 
is indeed as inseparable from the fact of gravita- 
tion as that fact is inseparable from our original 
notion and definition of matter. Herein, there- 
fore, we see wisdom, infinitely superior to man's 
wisdom, not in degree only, but in kind; and 
accomplishment, superior to anything that man 
can accomplish, not only in degree but in kind : 
—we discover in fact the living principle in the 
very simplest attribute of dead matter. Thus, gra- 



THE SPHERICAL FORM. 195 

vitation is, as it were, a seed sown by the Almighty 
in a soil the best adapted for its fructification, and 
its fruits everywhere fill both the heavens and the 
earth with beauty and usefulness. It is highly 
instructive to catch even passing glimpses of those 
wonders of creation — for truly they are the won- 
ders. We admit that the things themselves, 
which address themselves merely to the senses, 
are withal pleasing and delectable: but they are 
nothing in comparison with the system of work- 
ing which runs through the whole, possessing 
attributes which to us may well seem a combina- 
tion more than mortals could have dreamt of, — 
the perfection of simplicity, and the perfection of 
power, co-operating together, or rather, being one 
and the same. But if we find one single principle 
thus running through the whole of nature, and if 
we find that principle powerful and perfect to the 
utmost extent that material nature can bear, how 
can we, how dare we, resist the conviction that 
this is one work of one Being, all-wise, all-pow- 
erful, and, as the whole works for good, all-boun- 
tiful? 

We shall now very briefly notice one or two 
of the circumstances which modify the solar 
action, and would modify it, although the earth 
were at rest, and presented always the same hemi- 
sphere to the sun ; and this will simplify the case 
when we come to consider the modifications which 
are produced by the motions, whether diurnal or 
seasonal. 

The first cause of modification is the atmo- 
sphere, which, as we have mentioned, invests the 
earth in every direction, and which becomes more 
and more rare as it is higher and higher above 
the surface. The absolute height to which it 



196 ATMOSPHERIC MODIFICATIONS 

ascends above the earth is an inquiry which be- 
longs to the natural history of the air itself; so 
that we have only at present to consider the 
height to which it affects the beams of the sun as 
they fall upon the earth ; and here again we shall 
find that this substance, which answers so many 
important purposes, would tend to increase the 
benefit wdiich the earth derives from the solar 
beams, even though it ? as well as the earth itself, 
were in a state of rest. 

It is a property of light, that when it falls 
obliquely, or slantingly, on the surface of a trans- 
parent substance of denser nature than that out of 
which it comes to this substance, it turns into the 
denser substance, at a certain rate which varies 
with the nature of the substance and the degree 
of obliquity ; and of course it is a matter to be 
practically determined by observation for each 
particular substance. This property is called the 
refrangibility of light, and the change in any 
particular case is called refraction. 

It is another property of light, that when it 
falls upon surfaces it is in whole or in part turned 
away from those surfaces, and this turning is 
called reflection, which means bending back again. 
If the light falls obliquely, and is reflected in whole 
or in the greater part, it comes away from the 
surface at exactly the same angle at which it fell 
upon it, as it does in the case of a common mirror ; 
but. if it is reflected only in part, the rest of it 
follows the same law as when emanating from a 
luminous body, — that is, it proceeds in all direc- 
tions from every point of the surface. When 
light is thus decomposed by the surface on which 
it falls, it becomes, as it were, new light, — that 
is, light differently composed from the original 



ACTION. 197 

beam, and always wanting some of the elements 
which it had in that beam. This decomposition 
may extend to the whole of the light, or only to 
a part of it ; and as the light of the sun, when 
falling at the same angle, must be understood as 
always capable of producing exactly the same 
effect, the difference must depend on the nature 
of the substance on which it falls, and it is there- 
fore, like the former, a matter of practical obser- 
vation. 

This point is only incidental to our main sub- 
ject ; but it is one of great interest in the study of 
creation, because it involves the doctrine of all 
those colours with which natural objects are 
adorned. It is possible by refraction to obtain 
from the light of the sun, as thrown upon white 
paper, any colour, and any intensity of that co- 
lour, which it is possible to imagine ; and, there- 
fore, in order that an object may show any tint 
whatever, we have only to suppose that it sepa- 
rates the portion of light capable of producing 
this tint, thereby making new light of it, and 
causing it to be seen in any direction in which 
the object may be viewed. But this diffraction, 
or decomposition, of light at the surfaces of bodies 
may be combined with reflection there. The re- 
flection is always in proportion to the smoothness 
of the surface, and the obliquity at which the 
light falls on it ; and if these are beyond a cer- 
tain amount, the colour disappears, and nothing 
is observed but a shining surface. We have a 
very good instance of this in looking at a highly 
varnished picture, which hangs on the wall at 
the end of a room which is very near to a win- 
dow in the side ; if we stand near to that side 
where the window is, we see the colours of the 
17* 



198 COLOUR. 

picture, and they continue to be visible to us till 
we are a good way past the middle of the room 
in our progress to the opposite side ; but when 
we move to such a position as that two lines 
drawn, the one from the window and the other 
from our eye, make equal angles with the pic- 
ture, the picture disappears altogether, by the 
light being reflected ; and if the varnish were 
smooth and bright enough on the surface, and 
we saw it first from this position, it would be im- 
possible for us to tell whether we were looking 
at a picture or a dull mirror. It is worthy of 
remark,, that Nature's pictures never have this 
imperfection. It is true, that her most lovely 
colours seldom have any gloss ; but even in the 
case of those which have gloss, that gloss does 
not, like the varnish of a picture, present us with 
a blank, — it always gives us a beauty, and gene- 
rally a metallic reflection, as we find in the feath- 
ers of many birds. But we shall have occasion 
to enter more minutely into this very beautiful 
department of nature when we treat generally of 
the t/iir, the medium through which alone colour 
is displayed. 

From what we have said of the atmosphere 
and of light, it follows, that when light falls upon 
the hemispherical atmosphere, it must be diffe- 
rently affected at points which are at different 
distances from the centre of this hemisphere ; and 
that, as the atmosphere becomes the denser the 
nearer we approach the surface of the earth, the 
light must be more and more affected as it gets 
nearer to the surface. We may mention, that 
the clear atmosphere does not, to any very sen- 
sible amount, diffract, or decompose, light ; and 
that is the reason why, when seen from the sum- 



ATMOSPHERIC REFRACTION. 199 

unit of a very lofty mountain, the cloudless sky 
is very nearly black ; but when there are foreign 
substances in the atmosphere, such as particles of 
vapour, or very minute dust, of which there is 
often a great quantity, though nothing but the 
light can detect it — just as nothing can detect the 
motes in the sun-beam but that beam itself, — 
and these floating substances, and the substance 
of the air itself, supply, by their action on the 
light, all the varied colours of skies and clouds 
which we observe, and also all the light which 
prevents the shadow from being absolutely dark, 
and forms, the twilight, by means of which the 
light and darkness fade into each other by the 
most gentle and the most delightful gradation. 

At the middle of the hemisphere, the light of 
the sun must fall perpendicularly, or right down 
upon the surface of the atmosphere, and there- 
fore it will not be refracted there ; and that it 
should not is very obvious, for this simple reason, 
— that if it is proceeding right into the atmo- 
sphere it cannot go "more right" into it. But 
everywhere else it falls obliquely ; and the obli- 
quity increases toward the boundary of the hemi- 
sphere in the rate above stated, till, at the very 
extremity, it passes over the surface, and has no 
effect whatever. 

Now, up to a certain point at least, the refrac- 
tion increases with the obliquity; and, in conse- 
quence of this obliquity, the light has also to travel 
a longer way through the same height of atmo- 
sphere than when it comes perpendicularly, or di- 
. reedy ; and on both these accounts it is evident 
that, as we recede from the centre of the hemi- 
sphere, the atmosphere will have more and more 
tendency to refract, or bend toward the surface of 



200 THE ATMOSPHERE. 

the earth, the rays of the sun ; and by this means 
again the very form of the atmosphere, which, 
like that of the earth, is a result of gravitation, 
tends to increase the action of the sun upon those 
parts of the earth's surface at which, on account 
of the form of the earth, that action is diminished. 

It should seem that the upper part of the at- 
mosphere is, so to express it, "fined away" into 
surrounding space, so that the commencement of 
it has no effect whatever upon light ; for we can- 
not say that there is either a definite beginning 
or a definite end of twilight, though of course 
there is of our perception of it^ neither can we 
say what might be the effect of the sun-beams in 
the case of an atmosphere wholly divested of 
moisture, or other foreign substances, for we have 
no experience of such an atmosphere ; and though 
we were to imagine one, we could not imagine 
any use for it. We have said, that the atmosphere 
is the "messenger," and if there is no message 
the messenger is useless, and may be discharged. 

To what extent, and whether to any extent, 
this beneficial effect of the atmosphere — in send- 
ing down an additional portion of the solar in- 
fluence to those places of the earth on which the 
direct light of the sun falls obliquely — may be 
diminished by the reflection of light from the air 
itself, or from the particles of moisture, or other 
foreign substances floating in it, we have no means 
of judging ; but though there is no doubt that 
when the reflecting substance acquires the densi- 
ty of a black cloud overshadowing the whole ho- 
rison, it may be a source of cold, and certainly is. 
a cause of darkness ; yet, when the air is suffi- 
ciently clear for allowing the light of the sun to 
reach the earth unbroken, the reflection from 



PARTIAL REFLECTION. 201 

these particles can have but a trifling effect ; and, 
in the case of heat radiating from the earth to the 
colder atmosphere over it, we have evidence that 
clouds diminish this operation, and render the 
cold less intense than it otherwise would be. 
This is a subject, however, which belongs more 
to the doctrine of the air. 

The other causes which, on the supposition 
that the earth is still, and the sun shines constantly 
on the same hemisphere, tend to modify the solar 
action, are the different kinds of substance and 
surface upon which the beams of the sun fall. 
This is an extensive as well as an intricate inqui- 
ry, and it is one of experiment, and as such almost 
requires to be treated as a distinct science ; so 
that all which we can pretend to accomplish is, 
simply to point out the general principles; and 
w r e shall do this with reference to only three 
principal kinds or characters of surfaces : first, 
the surface of water ; secondly, land covered with 
abundant vegetation ; and thirdly, land which is 
bare of vegetation, or nearly so. 

In the case of water, 18 parts in 1000 are re- 
flected when the light falls perpendicularly ; 22 
parts when it falls at 40° ; 200, or about one-fifth, 
when it falls at 75° ; 501, or nearly one-half, when 
it falls at 85°; and 725, or rather less than three- 
fourths, when it falls at 89 §°i From these pro- 
portions, which are the results of experiments 
carefully made, it will be seen, that near the 
middle of the hemisphere the increase of reflection 
from the surface of the water is comparatively 
small : but that it increases very rapidly toward 
the extremities of the hemisphere, so that at 75° 
there falls only half the influence, — rthat is, only 



202 SUN-BEAMS ON WATER. 

half acts upon the surface of the water, and the 
other half is reflected into the air. Of the quan- 
tity so reflected, however, a considerable portion 
must expend its energy in heating the air; and 
this heating of the air by sun-beams reflected from 
the water is one of the principal causes why the 
polar seas are so much involved in fogs during 
the hot season ; and the reflection of it by the sur- 
face is the chief reason why, when the sun be- 
comes low, the surface of the water so speedily 
freezes in those parts of the world. 

But we have seen that, even where the light 
falls perpendicularly, eighteen parts in the thou- 
sand, or about one-fifty-fifth of the whole, is re- 
turned by reflection ; and therefore, even under 
the most powerful action of the sun, and inde- 
pendently altogether of the portion of that action 
which is consumed in evaporating, the entire ef- 
fect of the sun-beams falling on the surface of the 
water cannot be exerted in heating that water. 
In this case, however, as well as in the other, the 
portion which the surface of the water returns by 
reflection must be in great part applied to the 
warming of the superincumbent air ; so that water 
has always a tendency to preserve a greater uni- 
formity of atmospheric temperature, and, conse- 
quently, a greater uniformity of climate, than can 
be expected upon the land. 

Surfaces covered with thick vegetation reflect 
less of the sun-beams than any others ; they bear 
to the surface of the water nearly the same re- 
semblance which velvet does to a mirror, and to 
the bare earth a resemblance not unlike that which 
velvet has to plain stuff. But vegetables in a 
state of growth absorb the greater part of the sun- 



RICH SURFACES. 203 

beams which fall upon them ; and as they present 
a far greater surface camparatively humid than 
the portion of the earth which they occupy, and 
as evaporation goes on — at least under the direct 
action of the sun — at every part of this surface, 
the evaporation from a close vegetation must be 
not only greater than from the bare earth, (where 
there is, in truth, little to be evaporated,) but 
greater than from the same breadth of water as 
the surface which the vegetation occupies. 

But the leaves of vegetables under other cir- 
cumstances have the power of what may be called 
counter evaporation, — that is, they can take out 
of the air that moisture which it holds suspended 
in a state of invisible vapour, — and thus they 
may be, and are practically found to be, sources 
both of warmth and of dryness. It is easy to un- 
derstand how this must be the case : — the leaves, 
young shoots, and indeed all the active and grow- 
ing parts of vegetables, contain a great quantity 
of moisture in their substance, and very many of 
them contain far more than they can receive from 
the earth by means of the roots. This is not the 
case with air plants, which are not at all connect- 
ed with the soil, or with plants that grow in the 
dry sands, only ; for it applies equally to all sorts 
of vegetables, excepting perhaps those which ac- 
tually grow in the water. It is upon this prin- 
ciple that plantations of timber tend so very much 
to improve the climate and fertility of those coun- 
tries in which they are situated, by diminishing 
the heat of the torrid regions, and the cold of the 
tropical ones; and in this we see the beautiful 
provision which nature has made in the polar 
and the tropical forests, — for, under circumstances 



204 BARE SURFACES. 

favourable to their growth, forests are more abun- 
dant there than in the middle latitudes. 

Lands bare of vegetation always tend to in- 
crease the particular character of the climate in 
which they are situated, because the light of the 
sun acts more powerfully upon them than upon 
water, or upon surfaces covered with vegetation. 
They absorb the greater part of the heat, that is, 
they themselves become more heated than the 
others; and, instead of producing any mitigation 
under circumstances of great heat, by the evapo- 
rating of moisture, they act as so man}' furnaces, 
heating the air over them by means of radiation. 

But they cool as speedily as they heat, and 
therefore under circumstances the reverse of those 
which heat them strongly they are cooled and 
tend to cool the air by abstracting heat from it. 
Thus, surfaces of bare earth, while they are the 
most unprofitable that the earth can present, are 
at the same time subject to the greatest extremes 
of climate; still, however, even they have their 
use in the general economy, because by the vio- 
lence of their action, they serve to put in motion 
the currents of the atmosphere. 

Such are a few of the principal effects which 
the atmosphere and the great component parts of 
the surface of the earth have in modifying the 
action of the sun, so as to produce those differ- 
ences of climate and productions which we find 
in different regions. We have mentioned them 
without reference to the motions of the earth, 
because though those motions produce very dif- 
ferent results from what would take place if the 
earth were at rest, and the shining constantly on 
the one-half of it, yet the motions only modify 



CO-OPERATION. 205 

ihe results, without in the least destroying the 
principles on which they depend. This may, 
indeed, be said to be the case in the whole of na- 
ture ; for, though we are accustomed to use the 
word, there is really no such thing in nature as 
an opposition ; and when cause modifies cause, 
however different the joint effect may be from 
the single one, it is always the effect of co-opera- 
tion ; the one, as it were, accommodating and as- 
sisting the other, and not conspiring against it. 
This is an understanding which we should carry 
with us in all our inquiries into natural subjects ; 
and if we could make it our own, take it into so- 
ciety with us, act upon it, and make every thing- 
there consent and co-operate, the World would 
certainly not be less pleasant or less profitable to 
live in, than it is with its strifes and oppositions, 
whatever ability may be displayed in the conduct- 
ing of these, and though, as is generally found to 
be the case, those who are really in the wrong are 
always most determinedly in the right. 

Our business in the next section will be to con- 
sider the influence of the earth's rotation upon its 
axis in modifying the solar action ; and in order 
to render this as simple as possible, and enable 
such readers as are not accustomed to inquiries of 
the kind to get as clear and as correct a view of 
the principle as possible, we shall take the very 
simplest case in which the subject can present 
itself; and then, if we succeed in making this in- 
telligible, we shall perhaps be able to make it the 
means of throwing light upon the more compli- 
cated cases. 

In treating of the effects of rotation, we shall 
have occasion to open up some views of the sub- 
18 



206 GRANDEUR OF CREATION. 

ject, which, we believe, are new, and to some 
may appear not a little startling ; but they will 
abide the test of the keenest scrutiny,; and we 
cannot too often repeat, that how much soever it 
may excite our wonder, we ought not entertain 
the slightest scepticism of the grandeur of any- 
thing which God has made. 



207 



SECTION X. 



The simplest view which we can take of this 
part of our subject, is that which occurs twice in 
the course of the year, when the sun is directly 
over head at the earth's equator, and the poles 
of the earth's rotation are in the extremities of 
the illuminated hemisphere. It is true that, in 
consequence of atmospherical refraction, the por- 
tion actually illuminated by the sun is a very little 
more than a hemisphere, and the twilight portion 
extends for some twelve degrees, or about 840 
miles all the way round this ; but, in the general 
consideration of the matter, these circumstances 
may be left out, only we must not forget that 
they actually exist. 

In this position of the earth, the plane of the 
equator is directed to the sun, or, if it could be 
seen from the sun, it would be projected into, that 
is, it would appear to the eye as, a straight line ; 
and as the axis of rotation is at right angles to the 
plane of the equator, and also to every parallel 
of latitude, the sun would shine upon exactly the 
half of each parallel, and the other half of each 
parallel, as well as of the equator, would be in 
the twilight and the dark. We need scarcely 
add, that as the earth turned round under those 
circumstances, every point on its surface would 
pass through the light, and the dark and twilight 
in equal portions of time, or that day and night 
would be equal at every imaginable place on the 
earth's surface. Farther, the height of the mid- 



208 PHENOMENA 

day sun above the horizon would he, at every 
place, equal to. the distance of that place from the 
pole; and the zenith distance of the sun at mid- 
day, or the sun's distance from the point over 
head, at mid-day, would be everywhere equal to 
the latitude. 

It will, perhaps, assist in forming a clearer 
notion, if we suppose that a cylindrical beam of 
light, equal in the cross section to the section 
through the earth upon a meridian, comes to the 
earth with its centre exactly on some point of the 
equator, and that the end of this beam, which 
falls upon and acts upon the earth and its atmo- 
sphere, embraces them as a hemispherical cup 
would embrace the half of a spherical ball. We 
have only to imagine the earth to turn round in 
this cup of light, on two points on opposite parts 
of the lip, and then we shall have a very efficient 
view of the matter. In the course of the twenty- 
four hours, that is, of one rotation, every point 
of the equator must come in succession to the 
centre of the cup ; and every other point, while 
it crosses an arch drawn across the hollow of the 
cup, through the two points of rotation and the 
centre, must cross this arch exactly as far from 
the centre as the place itself is from the equator 
on the earth. This is exactly the view which 
we would have if it were possible for us to get a 
sufficient way off and look at the earth. That, 
however, is impossible, and we are constrained 
to look from the earth, and thus both the position 
and the motion are reversed to our observation. 
But we need not perplex ourselves about this 
reversal, because we have instances of it in every 
case in which we can change looking at into 
looking/rom. Thus, when one looks at a mir- 



OP ROTATION. 209 

ror, and sees one's reflection (it is not an image, 
though so called in the books,) from the mirror, 
the right side is turned to the left ; and if one 
moves to the right hand, looking at the mirror, 
the reflection, as shown from the mirror, will ap- 
parently move to the left hand. The same, of 
course, happens in every case where we have a 
reverse view. 

The circumference of the equator is larger than 
that of any parallel, for its radius, or half the 
measure across it, is the radius of the earth ; and 
the radii of the parallels are the co-sines of the lati- 
tudes, — half the radius of the earth at 60°, as we 
mentioned in last section, and at the poles. But 
this difference of length makes no difference in 
the action of the sun upon the parallels, for they 
all travel across the hollow of the illuminated cup 
in exactly the same time; and as the influence of 
the sun is in itself invariable, the pole, which 
does not budge an inch, does not, on account of 
the rotation, receive less of that influence than 
the equator, which, in the same time, has travell- 
ed over 25,000 miles. But the light falls on the 
parallels at different angles, till, at the poles, the 
angle is 0, that is, the sun appears just in the 
horizon, therefore the influence of the sun upon 
the said parallels is in the proportion of the co- 
sines of their latitudes. 

When the sun is over the equator, therefore, 
the change which the rotation produces on the 
influence of the sun upon it from what that influ- 
ence would be if the earth were at rest, is merely 
to throw the influence which, in the case of the 
hemisphere at rest, is distributed into circles 
round the pole or centre of the surface of the 
hemisphere, into the equator and the parallels on 
18* 



210 ROTATION AND REST. 

the earth. The centre point of the hemisphere 
of light, as immoveable, is changed into the equa- 
tor; the circle 10° from that point is changed 
into latitude 10°, both north and south; and all 
the other circles are changed into the correspond- 
ing parallels till we come to the boundary of the 
illuminated hemisphere, which is changed into 
the two poles. 

This change is worthy of attending to, because 
that which is a single point, and the centre or 
maximum of the sun's action in the immoveable 
hemisphere, becomes the circumference of a great 
circle — namely, the equator, in consequence of 
the rotation ; and of the other circles, from the 
centre of illumination to the circumference, there 
is also a reversal in point of magnitude, for as the 
circumference of the fixed hemisphere becomes 
two points, namely, the poles, in consequence of 
the rotation, the circles, which were nearest the 
fixed circumference, and consequently largest, are 
now nearest the fixed points, the poles, and are 
consequently smallest. 

This has a considerable effect on the distribu- 
tion of solar heat, for if the point at the centre, 
which received the maximum heat when fixed, is 
expanded out into the circumference of a great 
circle, this great circle can receive the maximum 
action of the sun directly vertical over it only for 
one moment in the twenty-four hours; and in 
like manner, as the smaller circles are expanded 
into larger ones, the quantity of solar action to 
which they are exposed is proportionally dimi- 
nished by this expansion. It is true that the 
equator is still, in this position, the place of max- 
imum action of the sun, and the poles are the 
places of least action ; but all the actions — max- 



MODIFICATION OF HEAT. 211 

imum, intermediate, and least, — as told upon 
any point of any parallel, are very different from 
what they would have been had there been no 
rotation. 

This effect of rotation is worthy of some atten- 
tion, as tending to establish the grand truth of 
how beautifully all the parts of creation work 
together. We have seen that the necessary con- 
sequence of the rotation of the earth is the turn- 
ing of the heat at one point into the circumference 
of a circle, measuring about 25,000 miles ; and 
that each of the smaller circles round this point 
in the immoveable hemisphere are changed into 
the larger parallel circles. The heat at the equa- 
tor is, notwithstanding the seasonal and other 
modifications which we have not yet noticed, 
very great as compared with that, not at the poles 
merely, but 20° or 30° distant from them. But a 
circle of any dimensions is geometrical infinitude 
as compared with a point ; and therefore, had the 
earth been at rest the sun's action upon the illu- 
minated hemisphere would have been infinitude 
as compared with the present heat of the equator. 
It is impossible for us to estimate its intensity, or 
even to form any idea of it; but it would cer- 
tainly have been enough to turn, not merely into 
ashes,but into invisiblevapour, any substance upon 
earth of which we are acquainted. Were it not 
for its rotation, therefore, the earth could not be 
inhabited — nay, the probability, aye, the certainty 
is, that it could not exist. This is a fact as clearly 
established as the simplest which passes before 
our eyes; and it tends, in a manner peculiarly 
forcible, to impress upon us what a wonderful 
fabric creation is ; how fraught every part of it is 
with instruction, and how it speaks of the wisdom. 



212 EARTH AND MOON. 

the power, and the goodness of its Maker, in a 
language which no tongue or pen can embody in 
words. 

And we have a partial example of the conse- 
quences of want of rotation in the physical con- 
dition of our attendant, the moon. This body is 
not rotationless, for it makes one rotation every 
time that it revolves round the earth, and thus 
moves only 29h times slower in rotation than the 
earth does ; but notwithstanding, the moon bears 
evidence of the terrible effects of the sun upon a 
body which turns only at this rate ; for the moon 
is all over like the scoria of a furnace, or the ruin 
left by some destructive volcano. Yet, as we 
estimate rates of motion on the surface of the 
earth, the motion in rotation of a point on the 
surface of the moon is not so ver)^ slow, being 
rather more than ten miles in the hour. This, 
however, is very small, compared with the motion 
in rotation of a point in the earth's equator, for 
that is more than 1000 miles in the hour. We 
believe the elements of the ratio, at which the 
heating of a sphere diminishes, in consequence of 
its being made to turn on an axis, have not been 
investigated ; but the probability is, that the heat- 
ing is inversely as the squares of. the rates, and 
that the effect of the sun upon the equator of the 
moon is to the same on the equator of the earth 
as" 10,000 to 1. 

If all the matters which compose the aggregate 
of our earth as a planet, — solid matter, water, and 
air, — were carried along with it in its rotation, 
exactly in their places, or even making allowance 
for slow and local motions of animals, and other 
comparatively small substances, the general results 
of rotation would be as stated, and it would only 



COMPOUND MOTIONS. 213 

remain to consider the farther modifications 
arising from the annual motion, and to apply to 
them the secondary modifications arising from 
the nature of the earth's surface ; but there are 
some circumstances, connected with the moveable 
parts of the planet, which require to be noticed 
nefore the economy of the earth's surface can be 
rightly understood, though the full investigation 
of the principles, and the enumeration of the de- 
tails, belong to the history of the Air and the 
Sea, the parts in which those modifying circum- 
stances take place. 

To have a clear notion of the foundation of this 
matter, we must refer to a very general principle 
in mechanics ; and this reference will not be lost, 
inasmuch as the knowledge of this principle very 
frequently saves those who bear it in mind from 
serious, and even fatal, accidents. The principle 
is this : if any vehicle, or body of any kind, which 
can be considered as a carriage, is once fairly in 
motion, with all its load, at any given rate, every 
part of that load partakes equally of the motion 
of the carriage, and has no more tendency to fall 
while the carriage is in uniform motion, however 
rapid, than if the carriage were standing perfectly 
still; but if the motion of the carriage varies, it 
takes some time before this variation can be 
communicated to the load ; and if that load is not 
fastened, it is liable to be thrown off, if the varia- 
tion in the rate of the carriage be either sudden 
or considerable. If the motion of the carriage 
slackens, the load overruns it, and is thrown 
forwards; and if the motion of the carriage is 
quickened, it outruns the load, and that is thrown 
off behind. The knowledge of this principle is 
of great use to those who have occasion to travel 



214 MOTION IN BOTH 

on the outside of coaches, — and especially of 
coaches which are in the habit of making frequent 
stoppages. The accident to which a coach in 
motion is most liable, is stoppage ; and, therefore, 
the outside traveller should hold himself ready 
against this accident, which is easily done by 
keeping the body in a position reclining a little 
backwards. The same precaution is of use in 
boats, especially small boats, — large vessels do 
not get under way and bring up, so suddenly as 
to jerk their passengers overboard ; though, where 
a trim sailing smack is beating, and brings up 
through the wind, there is some danger that a 
landsman may measure the length of his back on 
the deck when the vessel first makes way on the 
other board. This is not our present subject, 
however ; and we merely mention a few points, 
that they may serve as an artificial memory of 
the principle ; and, having done so, we shall 
briefly notice how this principle applies more 
especially to the atmosphere. 

The earth may be considered as a great carriage 
rolling along through the regions of space, loaded 
with an immense number of passengers, and 
having all the loose inanimate substances as lug- 
gage. When these are solid, the gravitation and 
friction jointly act as a sort of tie, and keep them 
in their places. The water is more mobile, be- 
cause the parts of it move upon each other with 
little or no friction ; and the atmosphere is, to 
continue the simile, a sort of light "imperial" on 
the top of the carriage, which can hardly be said 
to have any fastening at all, but which remains 
steady as long as the part of the earth upon which 
it is carried has a uniform motion ; but the instant 
that the motion of the earth quickens, the air is 



ROTATION AND LATITUDE. 215 

left behind ; and the moment that the motion of 
the earth under it slackens, the air moves for- 
ward, and leaves the place where it was. 

With regard to its annual, or orbital, motion, 
considered simply, there is no perceptible varia- 
tion of this kind, either in the air or the water, 
because the size of the orbit is so great that any 
small portion of it hardly differs from a straight 
line ; and the change of the earth's rate of motion, 
from the slowest at the aphelion, to the quickest 
at the perihelion, and the reverse back again, is 
so gradual, that, before its change becomes at all 
sensible, it is communicated to the whole com- 
ponent parts of the planet — land, sea, and air. 

So, also, in the case of any loose body, or water^ 
or air, which retains its position in latitude,-— 
that is, does not shift either northwards or south- 
wards, — there is no tendency to difference of 
motion between it and the earth under it, and, 
consequently, no separation in lateral distance 
between the one and the other on account of the 
earth's diurnal motion of rotation. When, how- 
ever, there is a considerable change in latitude, 
happening in a comparatively short period of 
time, this change must occasion a difference of 
rate between the motion in rotation of the earth, 
over which the moveable body has come, and 
that moveable body. 

This explains itself, when we consider that the 
earth's rotation is performed on a perfect line ; 
that the extremities of this line have no rotatory 
motion ; that any point at the equator has a daily 
motion of 25,000 miles ; and that the motion of a 
point on any other parallel must bear the same 
proportion to this, which the co-sme of the lati- 
tude of that parallel bears to co-sine 0°, which 



216 MOTIONS ON 

is the latitude of the equator. We shall not go 
into the particulars, and especially not into the 
calculation; but, as before stated, the co-sine of 
60° is equal to one half of the co-sine 0°; and, 
therefore, any point on the earth's surface, or the 
air, tlie water, or any other substance, carried on 
the surface of the earth at that point, must be car- 
ried just half as fast as at the equator, that is, at 
the rate of 12,500 miles a day. North of this, 
the daily motion in rotation is less than half that 
at the equator, and it lessens very rapidly, as 
places are nearer to the pole, the point at which 
it ceases altogether. On the other hand, between 
the parallel of 60° and the equator, the rate of 
motion must be greater than half the equatorial 
rate, the variations becoming less and less for 
equal changes of latitude, till we approach nearly 
to the equator; and then, for some two or three 
degrees, there is very little difference, as the co- 
sine of the latitude there differs very little from 
co-sine 0°. 

We are therefore to regard the earth as being, 
in its diurnal rotation, a carriage of many motions, 
— of motions increasing, from rest at the poles, in 
the proportion of the sines of the polar distances, 
or complements of the latitudes to 90°, to a rate 
of 25,000 miles a day at the equator; or, if we 
view them in the other way, as commencing at 
the equator, then they decrease in the same pro- 
portion the reverse way : that is, as the co-sines 
of the latitudes, (which are exactly the same as 
the sines of the polar distances,) from 25,000 
miles a-day at the equator, to perfect rest at the 
poles. In this range there is an unbroken suc- 
cession of change, though the rate of increase 
is a decreasing one, if we view the matter from 



DIFFERENT PARALLELS. 217 

the poles to the equator ; and the rate of decrease 
is an increasing one, if we view it from the equa- 
tor to the poles. It is exactly the same in both 
hemispheres ; that is, on the north side of the 
equator, and on the south ; for when we speak of 
the two hemispheres, without any qualifying epi- 
thet, we always mean the two portions into which 
the equator divides the earth's surface, and not 
the hemispheres, which, in our map, are repre- 
sented on the plane of a meridian. In the two 
hemispheres the rates of daily motion, as to north 
and south, are of course reversed, because the 
poles are on opposite sides of the equator ; and 
the hemispheres are considered simply as halves 
of the earth, and, without reference to their va- 
rieties of surface, the exact reverses of each other ; 
so that whatever tells northward in the one tells 
southward in the other, and conversely. It is 
only necessary, besides this, to bear in mind, 
that the earth's rotation is performed eastward, in 
order to understand how the motions of the at- 
mosphere are affected by the different rates of 
motion, in- rotation, of the different parallels. 

At the poles, unless affected by some external 
cause, there can be no tendency in the air to 
move either way ; because the pole has no motion, 
except the orbital one ; and this, as we have said, 
is so gradual in its changes, that it cannot in the 
least disturb even the lightest loose substance on 
the surface of the earth. But the equator, and 
every thing situated on the equator, whether air 
or not, is carried eastward, at the rate of 25,000 
miles a day, or more than 1000 miles in the 
hour; and this rate of motion diminishes as 
we recede from the equator towards either pole. 

Now, it will readily be seen, that if any loose 
19 



21S MOTION IN CHANCE 

substance, such as the air, is, by any means, car- 
lied from nearer the pole to nearer the equator, 
it must have less motion eastward, in rotation, 
than the lower latitude into which it arrives, and 
that, if we could suppose the air over the pole 
instantly transported to the equator, the difference 
between its motion in rotation, and that of the 
earth at the equator, would be the whole 25,000 
miles in a day. The obvious consequence, upon 
the mechanical principle which we have men- 
tioned, would be, that this air would remain at 
rest, in respect of rotatory motion, and that the 
earth would escape eastward from it at the rate 
of 25,000 miles in the day, or more than 1000 
miles in the hour. But we estimate rest from 
the earth, and not from the atmosphere; and, 
therefore, the feeling to an observer at the equa- 
tor would be, that this air, instantly transported 
from the pole to the equator, moved westward 
at the rate of more than 1000 miles an hour; or 
it would become an east wind, blowing with that 
velocity. 

In reality j air cannot be instantaneously trans- 
ported from the pole to the equator, because air is 
a material substance, although one of compara- 
tively little specific gravity; and therefore it 
must take some time of the operation of any cause 
to move it from one place to another ; and it would 
take a comparatively long time to move it along 
the quadrant of a meridian, from the pole to the 
equator, which, is a distance of about 6250 miles, 
In the course of moving over this long distance, 
even if we were to suppose air to come all the 
way from the pole, it would gradually acquire a 
portion of the motion in rotation of the different 
parallels over which it passed j and it would ac- 



OF LATITUDE. 219 

quire more of this in proportion as it's own rate 
of motion toward the equator were slower. We 
are not practically acquainted with any motion of 
the air, in any direction, exceeding 100 miles in 
the hour, which is the velocity of those destructive 
hurricanes which occasionally visit some parts of 
the world, and are always productive of mischief. 
This is only about one-tenth of the rate of motion 
in rotation at the equator ; and therefore the na- 
tural motion of any current of the air arriving at 
the equator, either from the north or the south, 
must be far less than this ; for the hurricane is a 
disturbance of the air, and not a natural motion. 
It arises from the sudden action of some expan- 
sive force, or the sudden destruction of some re- 
sistance. Thus, for instance, if a heavy rain were 
to fall upon a thirsty desert, which had been long 
dry, and to which, in consequence, there had 
been a regular current of the air, or set of the 
wind from all sides, then the evaporation produced 
by the rain upon the dry and thirsty surface 
would bring a great degree of cold; this cold 
would condense, and bringdown the air over the 
desert, and stop the current which was moving 
towards the desert on the surface. The conse- 
quence would be violent winds in the neighbour- 
hood of the desert, until the current desertward 
were stopped, and the natural equilibrium of the 
atmosphere restored. 

But though no natural movement of the atmo- 
sphere toward the equator could carry the air 
there, possessing so little rotatory motion as to 
occasion anything like a hurricane from the east, 
yet it is perfectly evident that any surface cur- 
rent arriving at the equator, how slowly soever 
it might arrive, would have some less motion than 



220 AIR MOVING 

the surface of the earth at the equator ; and that 
this difference, whatever it might be, whether 
ten miles in the hour, one mile, or anything else, 
would give the air an apparent motion westward, 
which would be the counterpart of a real motion 
of the earth's surface eastward, just as the appa- 
rent motion of the sun, the moon, and the other 
celestial bodies. 

But air cannot arrive at the equator from either 
hemisphere, partaking of one motion only; be- 
cause as the motion in rotation is constant, and 
as on the parallels near the equator it is very 
little less than at the equator itself, air arriving 
at the equator must arrive there with very nearly 
the same rate of motion in rotation that the sur- 
face of the earth has ; and this will hold though 
we suppose a current of air to set the whole way 
from the pole to the equator, because the farther 
it has to travel it must be the longer on the way, 
arid the more affected by the rotatory motion of 
the parallels over which it passes ; and as this 
rotatory motion is most rapid near the equator, 
no current of the air can, by any force with which 
we are acquainted, be made to set so strongly 
toward the equator as to produce a permanent 
east wind there, though at some distance from 
the equator there may be such a wind, unless 
under circumstances where it is counteracted by 
the nature of the earth's surface. But, even 
where there is no such counteraction, and a wind 
of this kind is felt, it is easy to see that it cannot 
be a wind blowing directly from the east, because 
if the current of air forming the wind is on the 
north side of the equator, it has a motion south- 
ward, and if on the south side of the equator it 
has a motion northward. It is thus, whether in 



TOWARD THE EQUATOR. 221 

the one hemisphere or the other, acted on by two 
forces, one impelling it towards the equator, and 
the other, the deficiency of its motion in rotation 
compared with that of the parallel over which it 
arrives, impelling it in a direction parallel to the 
equator. It is therefore affected by two forces 
acting at right angles to each other, and therefore 
the resulting motions must be in the diagonal 
of a parallelogram, the sides of which represent 
those forces. Thus, if the motion toward the 
equator, and the deficiency of rotatory motion, 
compared with that on the parallel, are exactly 
equal to each other, this current will become a 
north-east wind in the northern hemisphere, and a 
south-east wind in the southern ; if the motion 
toward the equator is the greater of the two, the 
resulting current of the air will be more nearly 
a wind blowing southward in the northern hemi- 
sphere, or a wind blowing northward in the south- 
ern : and if the deficiency of motion on the pa- 
rallel, or tendency of the air westward, is greater 
than its motion toward the equator, it will pro- 
duce a wind blowing more in the direction of 
from the east, in both hemispheres. 

On the other hand, if any cause whatever shall 
produce a current of the atmosphere toward the 
poles, the circumstances of this current will be 
exactly the reverse of those of a current from the 
pole to the equator. That is to say, such a cur- 
rent will leave the equator with an equatorial 
velocity in rotation, namely, a velocity of more 
than 1000 miles an hour, and though this velocity 
will gradually diminish as this current sets farther 
into the hemisphere, upon the very same prin- 
ciple which makes the motion in rotation of the 
polar current toward the equator increase as it 
19* 



222 MOTION FROM THE EQUATOR. 

advances, yet this current from the equator, or 
indeed from any lower latitude to any higher 
latitude, must arrive at that latitude with more 
motion in rotation than the surface of the earth 
has there, and the difference, whatever it may be, 
must become a greater motion of the air eastward 
than the earth has, or, which is the same thing, 
a west wind, that is, a wind blowing from the 
west. In speaking of all winds and currents of 
the atmosphere, we are accustomed to speak of 
them in the names of those points of the compass 
from which they blow, though the set of the cur- 
rent is really in the other direction ; for instance, 
a south wind is a northward motion of the air, a 
west wind is an eastward motion, and so on in all 
other cases. 

The west wind, produced by a current from 
the equator toward the pole, and it would obvi- 
ously be the same from the same cause in both 
hemispheres, must be subject to the same modifi- 
cations as a current from the pole toward the 
equator ; that is to say, as it proceeded it would 
lose part of its rate of motion in rotation, and be 
changed into a wind blowing from the south-west 
if in the northern hemisphere, and to a wind 
blowing from the north-west if in the southern 
hemisphere, and it would be more nearly in the 
direction of from the west, or from the north in 
the one hemisphere, and the south in the other, 
according as its excess of motion in rotation, or 
its motion from the equator were the greater of 
the two. 

These considerations are, strictly speaking, 
parts of the natural history of the Air, but it is 
altogether impossible to form any notion of the 
general economy of the earth's surface without 



CAUSE' OF THE AIR S MOTIONS. 223 

them ; and thus we have no alternative but that 
of at least mentioning the outlines of them in this 
place; nor need we apprehend exhausting the 
doctrine of the air by such brief hints as these, 
because, when we come to take up that beautiful 
department of nature as our principal subject, we 
shall find no want of matter, and matter of the 
greatest interest. 

From what has been said, the reader will per- 
ceive that, in order to put the whole atmosphere 
in motion, we have only to imagine some cause 
which shall set it in motion at the equator ; and 
the reader must have anticipated, that exactly 
such a cause presents itself in the sun. The sun 
apparently travels westward round the equator 
at the times of the equinoxes (and these are the 
positions of the earth with regard to the sun which 
we are considering in the present section,) at the 
rate of more than 1000 miles an hour, — that is, 
as the earth turns eastward at this rate, the point 
where the sun is vertical apparently travels west- 
ward at the same rate, being in fact the counter- 
part of the earth's motion, as told upon the 
heavens in looking from the earth, upon the same 
principle that one's reflection is reversed when 
one looks from one's self at the mirror. 

We stated formerly that air is perfectly obe- 
dient to the influence of heat, and that it is im- 
possible to apply heat to any portion of it without 
causing that portion to expand, occupy more 
space, and constantly be specifically lighter : — 

Consequently, as the sun apparently moves 
round the equator, the air at the points where, in 
succession, the sun appears to be vertical, must 
be, from what has been already said of the max- 
imum effect of the sun-beams when they fall 



224 ACTION OF THE SUN. 

perpendicularly, more heated than any where 
else. Being heated, it must be expanded ; and 
being expanded, and thereby becoming specifi- 
cally lighter, it must ascend into the upper part 
of the atmosphere until it arrives at a height 
where the mass of the air has the same specific 
gravity as itself. That it must ascend is evident, 
for it cannot expand downwards into the earth, 
because every crevice which can be filled with 
air is always filled with it, in consequence of the 
remarkable thinness or rarity of that fluid, and 
its equal pressure in all directions. As little can 
it expand laterally, at least beyond very moderate 
limits, because the air there is colder, and there- 
fore denser, and consequently capable of offering- 
more resistance than the heated air, and must in 
fact press it upon it and force it upwards, upon 
the simple principle of the tendency of all fluids 
to maintain a perfect equilibrium or balance in all 
their parts. 

Thus, we may assume as a general fact, and 
observation establishes the truth of the assumption, 
that, at the point where the sun is vertical, there 
is a constant rarefication and ascent of the air, 
and a constant setting in of the surface-air from 
all sides to supply its place, until this surface-air 
becomes heated in its turn, and is rarefied and 
replaced. It is not exactly at the point where 
the sun is vertical that this maximum, rarefaction, 
and ascent of the air take place. The heat of the 
sun, though a powerful cause, is still only a 
material and finite one, and therefore it cannot 
produce any effect instantaneously, but must re- 
quire time, which is an indispensable element in 
all action of matter. Besides, there is no definite 
spot upon which this maximum action of the sun 



ACTION OP THE SUN. 225 

falls, for though it is greatest at the centre, the 
diminution is gradual throughout the whole illu- 
minated hemisphere ; and, unless in so far as 
depends upon different kinds of surface, which 
belongs to the earth, and not to the sun's action, 
there is no change perceptible from any one 
point, or even for several miles, in juxta-position 
with each other. 

Taking all these circumstances together, it is 
easy to see that the period of maximum heat 
must be after the time when the sun is vertical, 
and, consequently, in latitudes where the sun is 
never vertical it must take place after the time 
that the sun passes the upper meridian, that is, 
after twelve o'clock at noon. We are not, in 
the meantime, to draw any conclusion from this 
fact, but it is necessary to have all the circum- 
stances of the case fairly and clearly before us, 
and then many of the applications will suggest 
themselves. 

We are then to understand generally that, when 
the sun apparently travels vertically round the 
equator, the solar influence extending just to both 
poles, and no farther, and all places in both he- 
mispheres enjoying equal day and night, the 
maximum influence of the sun apparently travels 
westward, a little behind the place where that 
luminary is vertical, and there gives to the air of 
the atmosphere that primary motion which ulti- 
mately makes it circulate over the whole earth, 
and produce so many beneficial effects. From a 
certain space around this point of maximum effect, 
the air is constantly ascending, and there is as 
constant a replacement of it by the air from the 
other parts of the earth. The earth, and conse- 
quently the air over it, must, from the increasing 



22G THE TROPICAL ZONE. 

obliquity of the sun's rays, become colder and 
colder as the equator is receded from, though, 
because there is little difference in the position at 
which the light falls, for several degrees on each 
side of the equator, there must be nearly equal 
heat there; and therefore the maximum effect 
may be regarded as not travelling round the 
equator merely as a line, but as passing over as a 
zone of some considerable breadth, say two or 
three hundred miles. The breadth of this zone, 
and the fact of its being heated sufficiently, — in 
order to occasion such an expansion and ascent of 
the atmosphere as shall produce a wind from the 
north-east, or some point between the north and 
east, in the northern hemisphere, and a wind from 
the south-east, or from some point between the 
south and east, in the southern hemisphere, — 
depends, in a great measure, upon the surface 
over which this zone passes. If that surface is 
susceptible of the highest degree of heat, that is, 
if it is bare earth, not much elevated above the 
mean level of the sea, it will have the maximum 
temperature, and extend to the greatest breadth 
in latitude. If it is clothed with luxuriant vege- 
tation, the evaporation from that vegetation will 
consume a portion of the solar influence, and the 
effect upon the atmosphere will be diminished to 
the same extent ; and if it passes over the surface 
of the water, the effect will be still farther dimi- 
nished, though it is only over the uniform sur- 
face of water, stretching to a considerable extent 
on each side of the equator, that this current of 
the atmosphere can be distinctly perceived. 

If the reader will turn to the map of the world, 
he will find that the equator falls upon a com- 
paratively small portion of land, namely, about 



ACTION ON THE EQUATOR. 227 

10° in the oriental islands of Gilolo, Celebes, 
Borneo, and Sumatra, over about 30° of the con- 
tinent of Africa, and over about the same extent 
in the continent of South America, making in 
all 70° out of 360°, or seven thirty-sixths, or not 
much more than one-fifth of the entire circum- 
ference of the globe. The remaining 290°, or 
nearly four-fifths of the circumference of the 
equator, fall upon water; and by looking at the 
map it will be perceived, that it fills upon wide 
seas, uninterrupted by any land, except a few 
small islands. Farther than this, it will be per- 
ceived that the equator, with the exception of the 
interior of Africa, which is but little known — 
though the probability is that in this latitude it is 
not a desert, — that the equator falls upon lands 
which are covered with luxuriant vegetation. In 
the eastern islands the places immediately under 
it are perfect gardens; anil in America, it passes 
along the great valley of the Amazon, about half 
way up the left hand, or northern, branches, but 
still within the range of their fertilizing influence, 
and over a country which is, generally speaking, 
clothed with forests. Therefore, in so far as the 
land is concerned, the action of the sun on the 
equator — that is, immediately on the equator — 
snay be considered as being a minimum ; and as 
land forms so small a portion of the circumference 
of that great circle, the action of the sun, when 
over the equator, is principally resolved into action 
upon the water. In understanding the general 
effect of the sun upon ^he earth, it is necessary, 
therefore, to call to mind the effect which that 
luminary has upon water. 

The principal effect in this way is to evaporate, 
and thereby to occasion cold $ and this tendency 



228 ACTION ON WATER. 

may be considered as extending equally to the 
surfaces of rich vegetation over which the equa- 
tor passes, as to those covered by the ocean. In 
consequence of this, the influence of the sun upon 
the equator may be regarded as a minimum in- 
fluence, in respect of mere heating or burning up ; 
but the same circumstances which render it a 
minimum in this respect, make a maximum in 
benefit to the other regions of the earth. The 
evaporative power of the atmosphere, under all 
circumstances, increases with the heat; and as, 
when the sun is vertical, the portion of the sun- 
beams which are reflected from the surface of the 
water, without affecting the temperature of that 
fluid, are reflected back into the atmosphere, they 
tend to increase the quantity of evaporation ; and 
as, in addition to this, the surfaces over which 
the equator passes, have the maximum qualities 
for affording evaporation, it follows that there is 
not only a continual ascent of the atmosphere 
over the equator, but that the atmospheric fluid 
so ascending constantly carries along with it a 
large quantity of moisture. This moisture is 
borne into the upper regions of the air, and dis- 
tributed, by means of the counter currents, over 
both hemispheres, supplying them with the mat- 
ter of rain, one of the elements of fertility ; which 
also brings along with it the other element of 
fertility, namely, the action of heat. 

In this we see many advantages resulting to 
the habitable parts of our earth ; and it enables 
us to understand the motion of the oceanal waters, 
taken on the mean, or when the sun is on the 
equator ; from which it is by no means difficult 
to estimate what the effects must be when the 
sun is to the north or the south of that circle. 



EVAPORATION. 229 

Immediately under the equator, or rather in a 
zone of indefinite breadth,— of which the equator 
may be regarded as the centre, but which passes 
off by imperceptible degrees, both northward and 
southward, and may be said not entirely to cease 
till the poles are arrived at, at least, when the 
sun is over the equator, — there is a continual 
waste of water, or draining of water from the 
surface of the sea, and also from that of the vege- 
table clod, in consequence of the action of the 
sun ; and the consequence of this must be a con- 
stant tendency of the waters, especially of the 
surface waters, of the great oceans, especially of 
the Pacific and the Atlantic, which stretch, from 
polar ice to polar ice, from the polar regions 
towards the equatorial ; and the water so brought, 
evaporated by the equatorial heat, and returned 
again through the upper air, must contribute in 
no small degree to mitigate theclimate and increase 
the fertility of countries in both hemispheres re- 
mote from the equator. 

But the surface water, so moved from the polar 
regions toward the equatorial, must partake of 
that modification arising from increased rotatory 
motion in the earth, which we ha?" : -tioned 
as affecting the similarly directed current? r the 
atmosphere ; that is to say, as the surface waters 
of the ocean come from high latitudes, where the 
motion in rotation is comparatively slow, into 
high latitudes, where it is comparatively rapid, 
these surface waters must, so to speak, lag behind 
the bottom of the ocean, in its eastward rotation, 
or, in other words, there must be a current of the 
surface waters westward, on the same principle, 
though not to the same extent, that there is a 
current westward of the superincumbent air; and 
20 



230 CURRENTS OF THE 

this current is attended with the same beneficial 
effects as the aerial current, by equalizing the 
temperature of the ocean waters, in the same 
manner that the other equalizes the temperature 
of the atmospheric fluid. When we say "equal- 
izes/' we do not, of course, mean to say, that the 
temperature either of the sea or air is, or can be, 
the same in all latitudes, or that it would be the 
same even on the supposition that the whole 
surface of the earth were uniform, and equally 
affectable, by the action of the sun ; but it is true, 
that in consequence of both the oceanic and the 
atmospheric currents towards the equator, the 
maximum influence of the sun upon that particu- 
lar circle is distributed into the two hemispheres ; 
and, in consequence of the same, there is a general 
tendency westward given both to the waters of 
the ocean, and to the air immediately over the 
surface of the earth, while in the upper regions 
of the atmosphere there is a return current of the 
air, which carries water along with it, to replace 
the quantity which is evaporated in the equatorial 
regions. 

This is a very beautiful part of the working of 
the system ; and we cannot help admiring it, as 
showing, in the earth itself, upon the great scale, 
the same admirable wisdom, and the same per- 
fect contrivance and accomplishment, which we 
perceive in those minor works of nature, which 
we can take in our hand, or place wholly before 
our eyes. Indeed, we cannot look upon any one 
production, substance, phenomenon, or circum- 
stance, connected with nature, without perceiving 
how admirably each works, and how still more 
admirably all work together for the good of the 
whole. This is not, however, the whole of the 



AIR AND SEA. 231 

case, viewing even the simplest form of it, 
namely, that which supposes the sun to appear 
constantly in the equinoxial position, or directly 
over head at the earth's equator; for, -when we 
turn our attention to the poles, and especially 
when we take along with us the consideration 
between water and different degrees of heat, we 
see still farther what a glorious piece of work- 
manship the world is. 

We have, of course, no practical evidence of 
what the effect would be at the poles if the sun 
were to revolve constantly round the equator, 
either upon the supposition that the earth's surface 
were perfectly uniform, or taking it varied, as it 
now exists ; because heat is not a substance which 
we can either measure with the line or weigh in 
the balance, and, consequently, we can speak 
only about its observed effects. But from what 
has been said of the reflective power of the atmo- 
sphere, in sending down to the earth a portion 
of the solar influence, — which, if it were without 
the atmosphere, would pass effectless over it, — 
we may be sure that even in thrs state of things 
the poles themselves would not be left in abso- 
lute cold, but would enjoy some portion of the 
solar influence, however small. Now this mean 
position of things, or the sun over the equator, 
may be considered as the average of the year in 
both hemispheres, and, therefore, as that which 
we are to take as the basis of our investigation ; 
and though we cannot state what would be the 
temperature at the poles, as told by the ther- 
mometer, yet we may assume, from the result 
of actual observation, that in that state of things 
there would be a considerable zone round each 
pole, in which water could not exist except fro- 



232 THE SUN OVER 

zen, or in the state of ice or snow. Water thus 
becomes a most important element in all our ge- 
neral inquiries respecting the economy of the 
earth's surface. 

The icy zones could have no communication 
with the central, or equatorial parts of the earth, 
by means of currents; because, independently 
of other circumstances, the water there would be 
bound in fetters of perpetual ice. It is well 
worthy of our consideration to remark how beau- 
tifully the water is adapted to the degree of solar 
action on our globe; and that, while there is a 
certain equatorial portion, over which water is 
constantly converted into vapour, there would be, 
in the case of the sun constantly revolving round 
the equator, a portion as constantly sealed up by 
this congealing power, and retained at the poles, 
notwithstanding all the vigour of the solar influ- 
ence at the equator. And it is further worthy of 
remark, that there are, in almost every latitude, 
portions of the earth's surface which rise to such 
a height above the mean level as that they have 
this degree of polar cold, or, at all events, that 
they have cold enough for arresting and freezing 
a certain portion of the atmospheric humidity, 
and storing it up for the purpose of watering and 
refreshing those portions of the land which would 
otherwise be burnt up. 

These polar portions, with their perpetual ice, 
would of course be taken out of the influence of 
the general current, not only of the waters of the 
ocean, but of the atmospheric air ; and if the sun 
were to revolve constantly round the equator, the 
polar zones, to a breadth which we have no means 
of ascertaining, but which would exist to some 
considerable extent, would be the regions of de- 



THE EQUATOR. 233 

solation and of death — no, not of death, they 
would be regions of no life. 

. Besides this, it is near the poles that the dif- 
ference of velocity in rotation is greatest ; because, 
if we are to take a small portion, as, for example, 
a single degree round the pole, the circumference 
of that degree does not differ very much from a 
circle one degree in radius; and if we take 10° 
from the pole, the circumference of the parallel 
is not much more than one-hundredth part less 
than the circumference of a circle having these 
10° for radius, and is such that the motion in 
rotation there is between 180 and 200 miles in 
the hour, which is a very rapid rate, at the dis- 
tance of only about 700 miles from the pole. 
This motion in rotation is far greater than any 
impulse towards the equator which the sun can 
give to the atmosphere, even in the vicinity of 
that circle ; and therefore we can easily see that, 
upon the average, the atmosphere, not merely for 
10° round each, but for a much greater distance, 
must be, as it were, chained by the polar influ- 
ence, restricted to the polar region, and cut off 
from all connexion with the sun's action at the 
equator. And as the circumstance of there being 
a difference of seasons does not take the poles out 
of what would be their average condition if there 
were no change of seasons, but merely causes the 
heat and cold to alternate seasonally upon them 
in the summer and winter, it is evident that, in- 
dependently of varieties of surface, this is the 
average character of the polar climates. There 
is a general tendency in the east wind to blow 
constantly over those regions of the globe when- 
ever from any cause the atmosphere receives a 
motion towards the equator ; and, as we have said, 
20* 



234 RELATIONS OF 

the tendency of the surface air towards the 
equator is constant, it follows, by necessary con- 
sequence, that the tendency of the polar air is to 
circulate in the direction of from east to west, or to 
be an east wind, in all cases where it is not affected 
by differences of surface. But it is also evident, 
that as these portions of the earth are very little 
under the governing influence of the sun, local 
causes must have much more effect upon them 
than upon places nearer to the equator. Indeed, 
we may state it as a general truth, that the influ- 
ence of the sun diminishes all the way from the 
equator, or, taking the seasons into consideration, 
from the parallel at which the sun is vertical, to 
those places at which the sun appears just in the 
horizon. But as it is the law of nature, that when 
one cause ceases there is always an opposite cause 
to come into operation, it must appear evident that 
local circumstances must act much more power- 
fully in latitudes near the poles than they do in 
low latitudes near the equator; that, as there is 
a gradual diminution of the sun's controlling in- 
fluence from the parallel where the sun is vertical 
till we arrive at 90° distance from that parallel, 
so there must be an increase of the opposite causes, 
and that local circumstances must gain more and 
more power as the influence of the sun becomes 
less and less. 

We are therefore to consider the influence of 
heat as exerted by the sun, and the influence of 
cold, or congelation, as exerted in the absence of 
that luminary, as being laid against each other on 
the quadrant of the meridian from the equator to 
the pole. The sun's influence is a maximum at 
the equator, and (refraction excepted) at the 
poles ; and the action of congelation is a maximum 



HEAT AND COLD. 235 

at the poles, and at the mean level of the surface, 
0, or a minimum at the equator. 

In proportion as the solar influence predomi- 
nates, which is an influence exterior and extrinsic 
of the earth, it is evident that every terrestrial 
cause, be it what it may, must be held in subjec- 
tion ; and it is equally evident, that in proportion 
as this solar influence diminishes, every species 
of terrestrial must come more vigorously into 
play ; so that at the equator we have the maxi- 
mum influence of the sun, at the poles we have 
the maximum of local causes, and over the qua- 
drant we have the one increasing and the other 
diminishing, whether we estimate from equator 
to pole, or from pole to equator ; the equality of 
them, or the place where the one is as influential 
as the other, being theoretically about the middle 
of the quadrant, or at latitude 45° either way, but 
differing in reality from the varied surfaces which 
the earth presents. 

As there are, at opposite ends of the quadrant 
in latitude, two opposed and opposing actions, — 
a solar, or heating, action at the equatorial ex- 
tremity, and a cooling, or freezing one at the 
poles, — it follows as matter of course that if there 
is, in either hemisphere, an action by which the 
one of these is cut off from the other, and each 
confined more immediately within its own region, 
the effect of each within its own region will be 
greater than if they were allowed free intercourse 
with each other on the confines, by means of 
which the one would there mitigate or compensate 
the other. 

In our brief survey of the earth we saw that, 
in the northern hemisphere, both the eastern and 
the western continents reach northward to not 



236 STATES OF THE 

only the southerly limit of the polar ice, but to 
that latitude beyond which this ice is not melted, 
even in the heat of the northern summer. Hence 
it is easy to see that, in the northern hemisphere 
there can be no circulating current round the 
globe in high latitudes, either of the ocean waters 
or of the atmosphere; and not only this, but in 
fact that no current can circulate, in longitude, 
round any part of the northern hemisphere, be- 
cause in this hemisphere both continents extend 
from the polar ice to a considerable distance 
southward of the equator. Therefore, in the 
northern hemisphere we may state that there is 
a general connexion as between tropical and 
polar influence, except in so far as this influence 
is interrupted by ridges of mountains ; and it 
follows, by necessary consequence, that as sum- 
mer and winter alternate, their alternation of the 
play of the seasons must extend over a much 
greater range in latitude than if the connexion of 
those extremes to climate were broken by any 
definite natural barrier capable of retaining the 
solar influence more in the tropical regions, and 
confining the opposite influence, that of cold, more 
within the region of the pole. 

Even in this hemisphere we find in different 
longitudes very remarkable differences of climate 
and of seasons, arising from greater or less con- 
nexion between the lands and an open sea on the 
north. In the central part of America, the 
seasonal range in the high latitudes is a maximum ; 
for while there is a cloudless atmosphere and 
comparatively great heat, heat which burns up 
the vegetation, and leaves the rocks bare, almost 
to the very shores of the Polar Sea, during the 
summer months, the temperature there is so low 



TWO HEMISPHERES. 237 

for five or six months in the winter, that quick- 
silver hecomes solid, and may be hammered on 
an anvil. This intensity of cold during winter 
extends not only across the whole northern coast 
of America, but also along the whole of the north 
of Asia and of Europe to the islands of Nova 
Zembla, or about 60° east of the meridian of 
Greenwich ; and thence to about 40° west, or 
about 90° on the parallel of 70°, (indeed it is 
rather less,) is the only portion of the northern 
hemisphere which may be said to enjoy the ad- 
vantage of an open sea on the north. Bhering's 
Strait, between America and Asia, is too narrow 
for admitting any current of the Pacific to set 
toward the north ; and it is understood that the 
general run of the water there is southward, 
being in all probability the spent current of the 
Atlantic making its escape from under the polar 
ice. 

This Atlantic current, as will be seen upon 
examining the map, is turned by the oblique line 
of the east coast of North America and the island 
of Newfoundland, at which latter place it, in 
summer, meets with the " fresh/' or surface water, 
produced by the melting of the snows in the 
countries around Davis's Strait, Hudson's and 
Baffin's Bays, and the other land-locked seas on 
the north-east of America: and at the meeting 
there is an eddy, and a great deposit of the mat- 
ters carried by both currents, which deposit has 
formed the great bank of Newfoundland, which 
is the pasture of such innumerable shoals of fish, 
especially of cod. 

Thence the current sets eastward, against the 
shores of Europe, or, more strictly speaking, in 
the direction of the island of Spitzbergen, though 



238 ATLANTIC CURRENT. 

the coasts of Britain and Norway, and ultimately 
the islands of Nova Zembla, tend to turn it north- 
ward against the margin of the polar ice. In 
consequence of this, the countries round the 
White Sea, though more southerly in latitude 
than Lapland, have a much colder winter, and 
their summer is not so much refreshed by 
showers. 

But though this northerly current in the At- 
lantic tends to moderate the seasons in Europe,, 
rendering the winter more mild, and the summer 
more showery, and, therefore, less intensely hot 
than it otherwise would be under the- same lati- 
tude, yet this is not a circulating current in any 
beneficial sense of the word, but may be said to 
exhaust itself against the polar ice. In summer, 
when it has the greater intensity of motion, and 
also the greatest warmth, this current acts upon 
the huge masses of snow, or rather of ice, which 
accumulate in the dells and ravines of Spitzber- 
gen, and the other mountainous countries of the 
extreme north. The bases of those great masses 
are in the sea ; and the action of the current cuts 
them off, and they fall headlong with tremendous 
crashes, and make those regions of desolation 
terrific with the sound. Those icy formations 
are still more majestic towards the American 
shores, where the winter sets in with more vio- 
lence, and is of longer duration than on the north 
of Europe, and where, also, the break of the 
winter is more sudden. Those icebergs are often 
very large, being some miles in dimensions, and 
often at least two thousand feet thick, of which 
two-thirds are usually below the surface. Those 
masses are, however, phenomena of a seasonal 
character, and do not belong to the consideration 



ICEBERGS. 239 

of the earth's rotation on its axis ; though it is 
necessary to pay some attention to the difference 
of situation which these great bodies hold in the 
two hemispheres, because this enables us to see 
the effect of that free circulation which the air 
and the water have round the south pole at a 
comparatively low latitude. 

When we examine the southern hemisphere 
we perceive that almost the whole parallel of 35° 
falls upon the sea, or, at all events, there are not 
above 20° or 39° of it upon land, while this land 
is comparatively narrow ; and the only portion 
of it which is sufficient to interrupt the current is 
South America ; and the general position of the 
coast of that country merely throws this current 
southward, but not so far south as that it is at any 
time interrupted by ice. Hence the tropical 
influence is confined on the south side, and the 
polar influence on the north side, by the current 
in this sea ; and the heat of the one region, and 
the cold of the other, are both thereby augmented. 

What may be the character of the surface of 
our globe immediately around the south pole has 
not been clearly ascertained, though as high a 
latitude as 75° has been reached in some places ; 
but whatever may be the character of the land 
there, the icebergs float down into much lower 
latitudes than they do in the northern hemisphere, 
having been observed off the Cape of Good Hope, 
in latitude from 36° to 39°. Nor are these of 
very rare occurrence, or to be regarded as small 
fragments, for some of them have been found two 
or three miles in circumference, and rising from 
one hundred and fifty to two hundred and fifty 
feet above the surface of the water. The mass 
below water answering to this elevation above 



240 SOUTHERN HEMISPHERE. 

must of course depend in a great measure upon 
the consistency of the ice, but the average may 
be considered as about eight parts in the water to 
float one part above. 

It is highly probable, that though there are 
mountainous shores in the southern hemisphere 
upon which icebergs can be formed, yet that the 
polar surface there is not at any time so much 
heated during the summer as in the northern 
hemisphere ; and this again is a means of lessen- 
ing the intercourse by the air between tropical 
and polar latitudes in the south. When we ex- 
amine the whole hemisphere on the map, and see 
how little land is in it, and also that the different 
lands lie nearly on a parallel, and that the seas 
which separate them are everywhere of much 
greater breadth than the lands themselves, we can 
easily perceive that those countries will not an- 
swer to each other by any return of season or 
alternation of climate, as we have mentioned is 
the case between Africa and Australia, and the 
south of Asia. Each of the southern lands is 
thus, as it were, given up to its own climate ; and 
though this climate is, perhaps, not so very dif- 
ferent, upon the average, from the climate in the 
northern hemisphere as we might be led to expect, 
yet it is more uniform in the different seasons. 
The action of the sun on the surface of the water 
is altogether less than on the surface of land ; and 
it is probable that there is even less evaporation, 
as least at some seasons. By this means the 
southern hemisphere has the air over it much 
more uniform than the north ; and the conse- 
quence is, that the seasons, with the exception of 
the rains, are milder. In Van Diemen's Land, 
for instance, which is in about the same latitude 



SOUTHERN HEMISPHERE. 241 

as the north of Spain, the winter is as mild as in 
the very south of Europe, while the summer is 
not warmer than in the north of France. In 
other places of the south, the size of the lands, 
and the consequent distance of great part of them 
from the sea, has a considerable effect upon their 
character; but still greater uniformity through- 
out the year may be considered as the charac- 
teristic of these climates. 

The currents of the ocean, and of the atmosphere 
over it, have very considerable effect upon the 
characters of countries. As the motion both of 
the air and of the water on the surface is toward 
the equator, or the parallel of greatest heat, so 
the surface of both — that is, the ocean water and 
the air over it — must move towards the parallel 
of greatest heat with less velocity eastward than 
that parallel has ; and this must cause a westward 
current of the water, and a westward set of the 
wind over its surface. Of course the motion of 
the air must be by far the more rapid of the two, 
because it is more acted on by expansion of the 
parallel of greatest heat than the water is by eva- 
poration ; and also, because it is a great deal 
lighter than water. The result is, that while 
the current of the ocean is hardly perceived, ex- 
cept under particular circumstances, the current 
of the atmosphere produces a distinct and steady 
wind on both the wide seas, which is familiarly 
known by the name of the trade wind. 

On the principles already explained, this trade 
wind blows from the north-east to the northward 
of the parallel of greatest heat, and from the south- 
east on the south side of that parallel. Thus the 
trade winds of the two hemispheres act obliquely 
upon each other; and if the one is, owing to the 
21 



242 TRADE WIND. 

season, either different in temperature, or differ- 
ently charged with humidity, from the other, the 
result will necessarily be, the depositing of a 
quantity of that humidity and rain; and if the 
two trade winds are interrupted either wholly or 
partially by islands, they will also deposit a con- 
siderable quantity of their humidity upon those 
islands, or, indeed, upon any land which opposes 
itself to them. When we look at the map, and 
take the equator as the mean parallel of the great- 
est heat, we find two remarkable places against 
which the trade winds must tell in the manner 
which we have attempted to explain. Those 
places are the north-east portion of South Ame- 
rica, and the islands of the Eastern Archipelago, 
between New Holland and the south-east of Asia. 
This action tells singly upon America, only the 
form of that continent turns it to the northward. 
But among the oriental islands the effect is dif- 
ferent ; because of the reciprocating action which 
takes place across them, as it were, between New 
Holland and the dry countries of Southern Asia. 
As both New Holland and the Asiatic countries 
alluded to are dry for great part of the year, the 
heat is powerful upon them, and thus the mon- 
soon alternating from the one to the other than 
the set of the trade wind from the Pacific ; and 
therefore their seasons are much more varied 
than the seasons in the corresponding parts of 
South America, in which may be included the 
West India Islands. The continual meeting of 
the sea winds at those two places gives them, 
however, greater fertility and natural action of 
every kind than any other part of the earth's 
surface. 

Indeed, in every part of the world where we 



MONSOONS. 243 

have a sea wind setting toward the land, that 
wind is a cause of general fertility, as well as of 
mitigation of the seasons. This is especially 
felt in all those parts of Europe which ahut upon 
the Atlantic, and it tells upon them in a greater 
uniformity of seasons. Thus, in consequence of 
this action of the Atlantic, the winter is much 
milder in the British islands, and the north-west 
of F ranee, than it is on the same parallels in cen- 
tral Europe ; but on the other hand the summer 
is not nearly so hot, for while the vine country 
on the west of France scarcely reaches the lower 
valley of the Loire, it inclines to the north-east 
in the interior part of the continent, so that grapes 
come to maturity in the valley of the Rhine as 
far to the northward as the southern part of Eng- 
land, and farther to the eastward they come to 
maturity a good deal to the north of this. Not 
only so, but in the countries immediately to the 
north of the Black Sea, to which allusion has 
already been made, we have the fruits of tropical 
climates, such as the melon, and the water melon, 
growing freely in the open fields as a common 
crop, without any of that attention which is re- 
quired for the culture of even the cucumber in 
the warmest parts of England. From this it is 
easy to see that the effect of an insular situation 
must be greater uniformity of climate, though the 
weather may be more variable than takes place 
on extensive lands. If the island is situated in 
a tropical latitude the result is perpetual fertility, 
unless it happens to be within the range of a 
monsoon or shifting trade wind, and then it will 
have a rainy season and a dry. If, on the other 
hand, the island is situated far on the polar zone, 
tnid excluded from communication with the open 



244 ISLANDS. 

sea, as is the case with Nova Zembla, and the 
numerous islands on the north of America, the 
climate will make an approximation to perpetual 
sterility, more so than an extensive land in the 
same situation. 



245 



SECTION XL 

MODIFICATION ARISING FROM THE EARTH ? S 
MOTION IN ITS ORBIT. 

In order to understand the effects of this cause ? 
we must bear in mind the position which the 
axis of the earth's rotation maintains with regard 
to the motion in the orbit. In doing this, with a 
view to understand the effect on the earth itself, 
as producing seasons, it is not necessary to take 
into account the difference of rate at which the 
earth moves in different parts of its orbit, or the 
different distances at which it is from the sun. 
We have no absolute means of ascertaining the 
effect of these with anything like accuracy ; but 
the probability is, that as the relation of the ve- 
locity and distance is the same throughout the 
whole orbit, so that the radius vector always 
sweeps over equal surfaces in equal times, it is 
probable that the two causes of variation very 
nearly neutralize each other. 

We are therefore to consider the earth as re- 
volving with its axis always parallel to itself— 
that is to say, not shifting its position sideways, 
but making an angle of about sixty-six and a half 
degrees with the plane of the orbit. This angle 
is always made in the same direction, in conse- 
quence of the axis continuing parallel to itself, 
and therefore it must be inclined as much from 
the orbit in the opposite direction as it is inclined 
to it in the one first mentioned. This greater in- 
clination must, of course, be as many degrees 
more than 90°, which is a right angle, or the 
21* 



246 earth's annual 

angle of no inclination, that is, it must be 113£°. 
This, with the former, makes exactly 180°, or 
two right angles, the whole angles which a line 
can make with a plane. 

The radius vector, or line joining the centre 
of the sun and centre of the earth, which we may 
regard as being the axis or central line of the 
beam of solar action, which always falls upon a 
hemisphere of the earth, and the position of the 
radius vector, with reference to the earth's axis, 
must make in the course of the year, or time of 
performing a revolution in the orbit, all possible 
angles with the earth's axis between those two 
inclinations, that is, between 66%° and 113H°; 
and as we are to suppose that the radius vector 
meets the axis at the very centre of the earth, it 
will follow that the angle which the axis and radius 
form there will be always as much more than 90° 
told to the one end as it is less than 90° told the 
other way; 66£° is 23£° less than 90°, and 113^° 
is 23^° more than 90°, therefore the greatest de- 
viation, as told either way at the earth's axis, 
will be from 66%° to 113|°, and the deviation 
from a right angle both ways will be 235°. 

We are thus to imagine that the radius vector 
is a line fixed at the centre of the sun, and also 
that of the earth, and that the earth is carried 
round at the extremity of it in such a manner as 
that the axis upon which the earth turns makes 
66£° of an angle at the one end, and 113£° at the 
other ; that these angles continue becoming more 
and more nearly equal to each other as the earth 
is carried round, but always amounting to the 
same sum, that is, 180°, or two right angles, and, 
consequently, each being a right angle when they 
become equal to each other. When this equality 



MOTION. 247 

is arrived at, it is gradually lost, by the angle 
which was formerly the smaller now becoming 
the greater; and this equality continues to aug- 
ment until the particular angles are just the re- 
verse of what they were at the commencement, 
— namely, that which was llS^ at the com- 
mencement will now have become 66i°, and that 
which was 66%° will have become 113|°. This 
will take place after exactly half a revolution, 
and we may mention that these two positions of 
the radius vector and the axis are the perihelion 
or point nearest to the sun, and the aphelion or 
point most distant ; that the maximum inclination 
toward the south end of the axis, that is, the near- 
est approach of the radius vector to the south 
pole, is the place of the perihelion, and the situa- 
tion when the radius vector is most inclined 
toward the north pole is the place of aphelion. 
It of course follows from this, that when the ra- 
dius vector is equally inclined to both poles, or 
when the angle each way is 90°, the earth must 
be at the points of mean distance, or the extremi- 
ties of the shorter axis ; in which case the radius 
vector, by making equal angles with the axis 
both ways, will apparently travel westward di- 
rectly over the earth's equator, and the illumina- 
ted hemisphere will extend exactly to each pole, 
and the temporary influence of the sun upon the 
earth will be exactly the same, although the ra- 
dius vector (the extremity of which answers to 
the centre of the sun) always apparently travelled 
along the equator, and day and night were every- 
where equal. 

But we must not thence infer that there will 
be a medium climate in the two hemispheres or 
even at any one place in the same hemisphere, at 



248 EQUAL DAY AND NIGHT. 

those times when clay and night are equal. For 
there are many circumstances which require to 
be taken into account before we can even judge 
at what will be the action of the sun at those 
times ; and these modifying circumstances, which 
form the grand elements of our estimate of the 
actual climates of countries, depend partly on the 
motion of the illuminated hemisphere upon the 
earth, partly on the surface from which the radius 
vector has arrived, and partly also upon the pro- 
gressive history of the earth itself ; so that in the 
solution of this, the grand problem of geography, 
that which determines the inhabitableness and 
value of the earth, we must content ourselves 
with approximations, derived partly from theory, 
but much more from direct observation. 

Where the requisite data are so varied, so diffi- 
cult to be understood, so many of them unknown, 
and when, of those which are known, some are 
so contradictory of each other, it is hardly possi- 
ble to do more than give a slight view of the 
working of the system ; and in order to obtain 
even this view we must consider some of the ele- 
ments separately. Of these, the position of the 
illuminated hemisphere upon the earth is the one 
which is simplest in theory, and therefore it is 
the best for being made a general index or sort 
of artificial memory to the rest. 

We are to understand that under every position 
of the radius vector, with regard to that of the 
earth's axis, a cylindrical beam of light, that is of 
solar influence of every sort, equal to the section 
of the earth, including its atmosphere, falls upon 
these, and falls upon a hemisphere in the manner 
we have already explained, that is, with a maxi- 
mum influence at the centre or point where the 



ILLUMINATED HEMISPHERE. 249 

radius vector meets the surface, declining, or di- 
minishing; in the ratio of the co-sines of the dis- 
tances from this point, and becoming at the cir- 
cumference of the hemisphere. This illuminated 
hemisphere, which expression we use as a short 
name for all the effects which the sun produces 
upon the earth, is constant in its amount, and 
constant to the radius vector as its centre; and 
therefore, in order to understand how it applies 
to the earth at different times, in consequence of 
the earth's compound motions of revolution and 
rotation, we have only to examine the way in 
which the radius vector travels over the earth's 
surface. This travelling is of course apparent, 
and not real ; but it is the counterpart and mea- 
sure of the influence jointly of the two real mo- 
tions of the earth, and therefore when we once 
understand them, we need have no difficulty in 
understanding this, even though we speak figu- 
ratively of the radius vector travelling over the 
surface of the earth, instead of that surface really 
turning upon or through the radius vector. 

As the greatest deviation from a right angle — 
or the declination, as it is called — is, both ways, 
23|°, or more correctly about 23° 28', it follows 
that the radius vector must, at the opposite ex- 
tremities of the greater axis of the orbit, which 
answer to our mid-winter and mid-summer, be 
on, or appear to travel over, the parallel of lati- 
tude answering to the declination, of which 23^° 
is near enough for general purposes. We shall 
suppose the examination begun when the sun has 
its greatest declination south, or when the radius 
vector travels over about 23|° south latitude, 
which will be found to cross nearly the middle 
of New Holland, a portion of the Island of Mada- 



250 SOUTHERN 

gascar, Southern Africa, to the northward of 
Orange River, where the country is understood 
to be dry and barren, and South America, near 
the parallel of Rio, where the mountains on the 
east coast are high, and the plains in the interior 
become burnt up during the hot season. We 
shall afterwards return to the characters of the 
land and sea, and their relative proportions to 
each other, on the different parallels over which 
the radius vector travels at the different seasons 
of the year ; but it is desirable that we should no- 
tice them as we go along, and carry forward in 
our memories the accumulated mass of evidence. 
At this season of the year the radius vector travels 
only about 90° of land on the parallel, and 270° 
of sea, making in all .360°, the circumference of 
every parallel, and the lands passed over are wide 
apart from each other, and generally speaking of 
a dry and arid character, capable of being strongly 
heated, and of heating and giving a powerful as- 
cending motion to the atmosphere over them. 

When the radius vector travels over this pa- 
rallel of 23^° south, to which we give the name of 
the southern tropic, because the sun apparently 
turns there, and proceeds no farther into the 
southern hemisphere, it is within 66%° of the 
south pole, and 113^° distant from the north. 
But the illuminated hemisphere always extends, 
even without taking any notice of the refraction 
of the atmosphere, exactly 90° in every way 
around the centre of its surface, that is, the point 
over which the radius vector appears to travel. 
In this state of things, therefore, the sun will, 
during the entire rotation of the earth, shine 23^° 
beyond the south pole, but not shine on a zone of 
the same radius round the north pole. The earth 



TROPIC. 251 

will, in fact, turn with 23|° around its north 
pole, elevated out of the illumination, and at 
equal extent round the south pole, turned wholly 
into the illumination. There will, consequently, 
be no direct action whatever of the sun upon the 
northern polar zone, while upon the southern one 
that action will revolve round, the height of the 
sun being 23|° above the horizon at the south 
pole ; and in all places within the zone, the sun 
will be the polar distance of the place, that is, 
the difference between its latitude and 90°, more 
than 23|° above the horizon at mid-day, and the 
same quantity less than 23^° above the horizon at 
mid-night ; also, in all places of the southern hemi- 
sphere down to the tropic of the sun will be on 
the meridian to the north of the zenith at mid- 
day, and within the polar zone, on the meridian 
south of the zenith at mid-night 

At the tropic the sun will pass the meridian 
exactly in the zenith at noon, but it will not ap- 
pear to pass in a vertical semicircle, beginning in 
the east and terminating in the west, but will 
travel in an oblique circle, commencing to the 
south of east and terminating to the south of 
west. By this means, the sun's diurnal arc above 
the horizon will be a greater portion of the cir- 
cumference of a circle than when the declaration 
from the equator is less. Consequently the most 
powerful action of the sun upon the earth as count- 
ed for a single day, will be when the sun, that is, 
the radius vector, travels over the tropic. The 
relative lengths of the day in the different paral- 
lels are matters of easy calculation, and can be 
judged of with sufficient accuracy by means of a 
tolerably good globe; but we may mention that, 
when the sun travels over the southern tropic, 



252 SUN OVER 

day and night are at exactly equal length at 
the equator; that at the middle of the quadrant, 
or 45°, the sun rises at fifteen minutes past four 
o'clock, and sets at forty-five minutes after seven 
o'clock, making the day fifteen hours and a half 
long, and the night eight hours and a half, and 
this without making any allowance for the in- 
creased length of the day, which arises from the 
refraction of the atmosphere, and which, as that 
refraction is a maximum when the sun is in the 
horizon, and when the sun is in the zenith, the 
advantage resulting from it, and also the length 
of twilight, increases with increase of latitude. 

The state of the northern hemisphere, with 
regard to day and night, and consequently to the 
direct influence of the sun, without taking into 
consideration any of the modifying causes, is, at 
this season, the exact reverse or counterpart of 
that on the southern ; and in the other half of the 
year, when the sun apparently travels round the 
northern tropic, or 23^° north latitude, the cir- 
cumstances of the hemispheres are reversed ; and 
in so far as the sun is concerned, whatever influ- 
ence is exerted upon any parallel of the one of 
them in the one case, is exerted in exactly the 
same manner upon the corresponding parallel of 
the opposite- hemisphere in the other. It is not 
therefore necessary to go over the description 
a second time, at least in so far as this general ac- 
tion is concerned; because the only difference is, 
that the sun is seen as looking north at mid-day 
in the southern hemisphere, and seen by looking 
southward in the northern beyond the tropic. 

But when we come to examine the surface of 
the globe, where the northern tropic falls, we find 
it very different from that on which it falls in the 



THE TROPIC. 253 

southern. We have fully 75° of continuous land 
in Africa and Arabia, and the only interruption 
which this meets with in the Red Sea is so trifling, 
that it need not to be taken into the account. 
Then we have this northern tropic falling upon 
at least 45° of land eastward of the Arabian Sea, 
while the coast of Persia comes so near the tropic, 
and is at the same time so dry and warm, that 
we may admit it as being a tropical country. We 
have thus the northern tropic in the eastern hemi- 
sphere alone, stretching over an almost unbroken 
extent of 140° of longitude, which is about seven- 
eighteenths, or considerably more than a third of 
the whole parallel, while in the southern tropic 
the land occupies only a fourth of the parallel, 
and this fourth consists of parts far distant from 
each other, while Australia, the broadest of them, 
is not more than 40°. 

In the western hemisphere, the tropic falls 
much more upon the sea ; though, if we take the 
continuous range of the West India Islands, and 
bear in mind that local causes give a tropical cha- 
racter to the lower valley of the Mississippi and 
the country westward, we may say that there are 
not less than 40° of land upon which the tropic 
falls in the northern hemisphere. Adding this to 
the quantity in the eastern hemisphere, we find 
that the northern tropic falls upon land for 180°, 
or one-half of its extent, while the southern one 
falls only upon a quarter. 

This difference in extent of land, in longitude, 
cannot fail of making a wonderful difference in 
the sun's seasonal action upon the two hemi- 
spheres ; and there is no doubt that the characters 
of the lands themselves tend greatly to increase 
this difference. If we look at the map, we have 
22 



254 THE TWO TROPICS. 

the whole range of the African desert, Arabia, 
Persia, and India, to the foot of the Himalaya 
mountains, excessively dry at one seasomof the 
year, and much of them composed of rainless de- 
serts of sand, which, from the rays of the sun 
reaching all sides of the grains, is much more 
speedily heated than even a surface of indurated 
earth. It is true that, to the eastward of the 
Himalaya mountains, or rather of the mouth of 
the Ganges, is, comparatively speaking, a humid 
country, covered with immense forests, and, in 
great part, converted into swamps during the 
rains ; but the southern spurs of the Himalaya 
mountains, and the Bay of Bengal, cut off this 
eastern country from all connexion with the arid 
tracks to the west ; and therefore, we may con- 
sider the action of those tracks as being concen- 
trated and separate ; and farther, as the African 
part of it is cut off from communication with the 
Mediterranean, and all the rest abutting upon the 
Mediterranean country, which receives little or 
no ocean influence, we can easily see how power- 
ful an effect this vast tract of thirsty land, suscep- 
tible of the most powerful solar action, must have 
upon the seasons in the eastern portion of the 
northern hemisphere : and when we look toward 
the west, and bear in mind what the characters of 
the land are there, we can also perceive that, 
though different, the influence here must also be 
great, and much increased by the free communi- 
cation which the centre of North America opens 
up between the intertropical regions and those of 
the North Pole. 

On the south side of the equator we have no 
lands capable of affording such effect to the heat 
of the southern summer, or the cold of the south- 



THE HEMISPHERES. 255 

ern winter. From all that is known of Australia, 
it is by no means improbable that that vast island 
contains within it a sort of southern Sahara ; but 
still it cannot have either the same continued dry- 
heat, or the same comparative trail qtrrrrrty in the 
lateral motion of the air, as the north of Africa. 
Australia may be said to be placed in a sea of 
troubles ; for, with the exception of the north, 
where the land-locked sea is almost as hot as the 
land itself during the summer, it is exposed to 
the general current of the Pacific Ocean on the 
east, and the alternating monsoons of the Indian 
Ocean and the Southern Ocean, as far at least as 
the general current of the waters which confines 
the action of cold to the high southern latitudes, 
on the south and the west. There is also no spot 
in this great island at the distance of more than 
1000 miles from the sea on some -side ; and as the 
monsoon ranges more than this distance in India, 
and the trade wind of the Atlantic feels its way 
for more than 2000 miles up the great valley of 
the Amazon, there is no reason to conclude that 
any part of Australia is without rain. The storms 
of those seas are also no jokes ; and they are per- 
haps not so regular in the discharge of rain as 
those which beat upon and wear the slopes of the 
narrow part of America : they are, certainly, as 
violent when they do happen. 

Much of what can be said about Australia is 
conjectural; but all the evidence leads to the 
conclusion, that it is, in great part at least, a 
country which has been wasted by rain. In re- 
spect of latitude, New Holland ranges nearly on 
the same parallel with the last 25° of Southern 
Africa, — the last half of which is without the 
tropic, and the first half within, in the same man- 



256 AUSTRALIA. . 

ner as in Australia. Now, though Africa is the 
narrower country, upon the parallel, by more 
than one-third, yet the breadth of both is consi- 
derable ; and we may infer at least some simi- 
larity in their physical characters, and draw at 
least some conclusions respecting what is unknown 
of Australia, from what we know of Southern 
Africa. Now, .in Africa, the characters of the 
seasons are, violent rains with the one monsoon, 
and burning drought with the other. The rains 
fall with so much violence upon the indurated 
grounds, that the accumulated waters float off by 
the channels of the rivers, in the form of travel- 
ling lakes, which sweep every thing before them ; 
and, since the settlement at Sidney on the east 
coast of Australia, there has been evidence of the 
same violence of rain there. The rivers, as is 
the case in Southern Africa, have cut deep chan- 
nels through the solid rock ; and, on more than 
one occasion, the Hawksbury has risen to such a 
height as to sweep away all the crops and the 
buildings, and to teach the people to erect their 
dwellings above the level to which those floods 
extend. In the south-west too, the rains some- 
times scourge the country down to the very rock, 
and produce new land, and give rise to new ve- 
getation, in the hollows by the margin of the sea. 
The effect of those violent rains is the very 
opposite of what might, at first sight, be supposed. 
They break the soil in pieces, and separate the 
clayey particles, and also the saline ones ; and they 
hold these in solution, after they have deposited 
the sand and gravel. The clayey matter is thus 
carried into every hollow by the water which set- 
tles there ; and though it is originally dissolved 
in water, it effectually shuts up all the fissures 



AUSTRALIA. 257 

and pores of the earth, so that the water cannot 
penetrate and form reservoirs for the supply of 
springs, but remains on the surface, to be disposed 
of either by flooding to the sea, or by the progress 
of evaporation. Hence, on all the shores of Aus- 
tralia which have been visited, there are accumu- 
lations of rubbish, in which mangroves breed, and 
grow very rapidly, form barriers against the 
action of the tide, and occasion the formation of 
lagunes and marshes between their vegetable 
barrier and the original line of the coast. Behind 
these there is a gradual accumulation of all those 
finer particles of the soil which the heavy rains 
wash down from the more elevated parts; and 
thus when rain does fall, there is more violent 
surface action between water and air than in 
places where the water can penetrate the soil and 
form springs. From all that we know of the 
country, there is no reason to suppose that there 
are any lofty mountains in Australia ; and thus 
there is no interuption to the action of the sea 
over great part of it. So much evaporation from 
the surface produces a moderate degree of cold, 
even in the low latitude which this country oc- 
cupies ; and this, together with this action being 
as between sea and land round the whole country, 
renders the climate less variable than in corres- 
ponding latitudes of the northern hemisphere, or 
even than in Southern Africa, or the extra-tro- 
pical part of South America. 

But though we can thus see that there are great 
differences of action between the southern tropical 
sun in our winter, and the northern tropical sun 
in our summer, yet the quantity or land across 
which those two parallels lie, and the different 
characters of the lands themselves, are so mixed 
22* 



258 AUSTRALIA. 

up with the operations of other causes, that it is 
impossible to estimate their relative influences on 
the seasons in the two hemispheres with anything 
like accuracy. The inquiry also is farther em- 
barrassed by the fact, that the polar influence and 
the tropical are, in the southern hemisphere, 
separated from each other by the circulating 
current of the sea. We do know, however, from 
observation, that the characters of those southern 
lands are far more tropical, that is, far more uni- 
form, ever-green and ever-growing, in their sea- 
sons, than the same latitudes in the northern 
hemisphere. 

We have thought best to begin by a reference 
to the tropics, or times of extreme solar action in 
the two hemispheres ; because in this we most 
strikingly see the practical advantages which 
result to the earth from the simple fact of the 
oblique position in which its axis stands to the 
plane of the orbit, as taken on the line of the 
major axis, or line joining the points of aphelion 
and perihelion, in which it is at mid-summer and 
mid-winter, in the northern hemisphere, or with 
us, and at mid-winter and mid-summer in the 
southern hemisphere, or on the opposite side of 
the equator. The effect which this produces, 
when taken along with the consideration that it 
is the necessary result of the mere motions of the 
earth, is one of the most beautiful instances which 
we have of the very simple means by which re- 
sults of the highest importance are brought about 
in nature, by means so very simple that they 
altogether exceed, in the wisdom of their contri- 
vance, anything that could occur to r us in the 
course of our art. We should hardly expect 
before hand that the mere fact of the axis stand- 



259 

ing always at an angle of 66%° to the plane of the 
orbit taken in the direction of the major axis, the 
influence of the sun would be distributed with 
really more than double, nay, ten times the uni- 
formity over the surface of the earth, which it 
would have had, if the position of the axis had 
been at right angles to the plane of the orbit, taken 
in the position of this major axis, or line of the 
apsides in the orbit. Such, however, is the fact ; 
and it is a necessary fact, the result of the mere 
arrangement, without any additional waste of 
power or contrivance. That this connexion 
should be with the major axis of the orbit, and 
not with that of any other diameter, or of any 
other position of the radius vector, is also a beau- 
tiful part of the system, because it places this 
advantage which the earth derives on the basis of 
greatest stability. The major axis is the immu- 
table part of a planetary orbit, — the created part, 
as it were, — depending on the quantity of matter 
in the sun and the planet, and the velocity in 
motion which the planet had received at its crea- 
tion ; and it is more independent of the disturb- 
ances of other planets, or of any casualty whatever, 
than any other element of the orbjt. In conse- 
quence of the attraction of other planets, the earth 
may move faster or slower in some parts of its 
orbit during one revolution than during another; 
and the orbit may, from the same cause, swing a 
little upon the major axis; but this axis remains 
immutable in its position with regard to the sun, 
or, at all events, the variation to which it is 
subject — the change in the obliquity of the axis is 
exceedingly slow, and also contains in itself the 
means of its own compensation. 

It is impossible to reflect on those matters 



260 THE EARTH'S ORBIT. 

without being struck with the astonishing displays 
of wisdom and goodness which they set before 
us; and it is equally impossible to be so struck 
without feeling a higher degree of reverence for 
the bountiful Author of this wondrous system. 

The tropics are, for various reasons, the paral- 
lels at which, when the sun becomes vertical there, 
the solar action is greatest ; and they are so for 
various reasons. The circumference on the 
tropic is considerably shorter than on the equator ; 
and thus the motion in rotation through the light 
of the sun is slower, and the solar influence is 
greater. The circumference of the tropic is about 
22,600 miles, while that of the equator is about 
25,000. Thus the length of the tropic is about 
one-twelfth part less than that of the equator; 
and consequently, the tendency of the sun to heat 
the tropic must be greater than it is to heat the 
equator, for the simple reason that it is carried 
more slowly through the heating cause ; and we 
know, from experience, that the heat commu- 
nicated is in proportion to the slowness with 
which the body passes through the radiating heat. 
It is true that we are unable to apply our arith- 
metic to this, case, and state precisely by how 
much more the earth is heated, in consequence of 
the slower velocity in rotation of the tropic than 
of the equator; for the motion of the sun-beams 
is so very rapid, that we are unable to bring it 
within the limits of our calculation for anything 
but very long distances ; and besides, it is com- 
bined with the two motions of the earth — in the 
orbit and on the axis — in producing the effect; 
and those three motions we are unable correctly 
to estimate, though we know that some increase 
of heat must be the result, and that it must be 



HEAT ON THE TROPIC. 261 

distributed equally on both sides of the tropic ; 
though different causes modify its effects in these 
different situations. 

The increase in the length of the day, when 
the sun is overhead at the tropic, while day and 
night are constantly equal at the equator, is an- 
other cause why the vertical sun should produce 
a greater degree of heat there than at the equator ; 
and this cause is carried down increasingly into 
the higher latitudes of the hemisphere, over whose 
tropic the sun is, so that those polar summers, 
during the brief period that they are at their 
height, may, in the absence of evaporation, be as 
hot as the summers within the tropics. 

There is another reason — the variableness of 
the daily declination of the sun. The earth's 
orbit tells upon the surface of the earth, as a circle 
crossing the equator in two opposite points, and 
extending to the tropics, or to the latitudes of 
23|° nearly on the north and the south sides, 
though, on account of the motion of the equinox- 
ial points, this telling of the plane of the earth's 
orbit upon the surface of the earth cannot be per- 
manently represented by a fixed circle : because 
the equinoxes do not always happen in the same 
longitudes on the equator, or the solstices — that 
is, the mid-summer and mid-winter points — at 
the same longitudes on the tropics. But still we 
may, for general purposes, consider the equator, 
and this telling of the earth's orbit, which answers 
to the ecliptic, as two great circles of the earth 
considered as a globe ; that they bisect each other, 
or divide each other, into two equal parts, which 
are also equal to each other in the two circles ; 
and that their planes make an angle of about 23° 
on that equatorial diameter, the extremities of 



262 RATE OF CHANGE 

which, for the particular time, answer to the 
equinoxial point. 

Now, by examining any two circles of the 
same size which intersect each other on a map, 
or otherwise, it will be observed, that just mid- 
way between the intersections they are nearly 
parallel to each other ; and that this parallelism 
extends for a greater part of their lengths in pro- 
portion as the angle at which they intersect each 
other is less. In consequence of this intersection 
taking place at the equinoxial points, the sun's 
declination shifts very nearly one minute of lati- 
tude in the hour, though it shifts a little more at 
the spring equinox in March than at the au- 
tumnal one in September. At midsummer, when 
the sun passes vertically over the northern tropic, 
the change of declination is not one second of 
time in the hour, indeed not half a second ; and it 
is not much greater at the winter's solstice, when 
the sun is vertical over the southern tropic. In 
the first month after the equinox, or from the 20th 
of March to the 20th of April, the sun's longitude 
changes jiorth ward in round numbers rather more 
than 12°, or more than the half of its entire quan- 
tity ; whereas, in the last month immediately 
precedingthe summer's solstice, itdoes not change 
above 3°. The rate of changing is very nearly 
the same before and after both the equinoxes and 
both the solstices, so that the rates which have 
been stated may be regarded as an average of 
them all. 

In consequence of those differences in the 
change in declination the sun may be said to linger 
near the tropics for a considerable number of days, 
which days are not very perceptibly different in 
length ; and it is because there is scarcely any 
change in declination on the days of the tropics 



IN DECLINATION. 263 

themselves, that these are called the solstices, — 
that is, the times at which, in respectof declination, 
the sun "stands still. " This lingering of the sun 
for several days very nearly on the same parallel 
of latitude, once in each hemisphere, at opposite 
times of the } r ear, and at those times when the 
solar influence is alternately a maximum in each, 
enahles each hemisphere to have a winter's repose, 
long in proportion as the latitude is high, though 
much modified by local causes ; and also, alter- 
nating with this, a continual period of heat, during 
which the temperature, up to pretty high latitudes, 
is certainly not less than the average of what it is, 
under ordinary circumstances, within the tropics. 

When the sun has arrived at the equator— that 
is, at the end of a quarter of a year from the tro- 
pic — the rate of declination has become the great- 
est possible; thence to the next tropic it dimin- 
ishes, in the same rate that it increased ; and it 
increases again during the third quarter ; is again 
a maximum when the sun is again over the equa- 
tor ; and decreases during the fourth quarter, until 
it arrives at the tropic at which the estimate is 
begun, and the revolution of the year is com- 
pleted. 

If we could view this annual path of the earth 
from the sun, we should see it told upon sur- 
rounding space as a great circle of the sphere of 
the heavens ; but we see it as looking from the 
earth at the sun ; and therefore, if there were no 
rotation of the earth it would be told upon the 
sphere of the heavens as a great circle, of which 
the earth is the centre. But we do not see it in 
this simple way, for our observation partakes, as 
we ourselves do, of the earth's motion in rotation ; 
and therefore, if we were to collect the results of 



264 APPARENT ANNUAL MOTION. 

a year's observations, the joint motions of the 
earth, annual and diurnal, would be told in an 
apparent motion of the sun in the sphere of the 
heavens in two spiral lines, the one twisting round, 
in between 182 and 183 coils, from the southern 
tropic to the northern, and the other twisting 
round back again, in an equal number of coils, 
from the northern to the southern. The sun's 
daily change of declination, taken at the same 
hour, at noon, for instance, would be the distance 
between every two coils ; and thus these would 
appear to be very close to each other at the tro- 
pics, but they would gradually widen toward the 
equator, at which their distance would be the 
greatest possible. The space of the heavens 
upon which this double spiral would be told, 
would be that over head to the intertropical zone 
of the earth, or 235° each way, or 47^° in all, in 
breadth. Thus the sun must appear directly 
overhead only once in the year at each tropic, — 
namely, on the midsummer day in the hemi- 
sphere answering to that tropic, only it would 
continue without being at any perceptible distance 
from the zenith. But within every other latitude 
within the tropics, the sun must pass directly 
over head at mid-day twice in the year, once be- 
fore the midsummer day and once after it ; and 
we shall not err much if we consider these two 
days as two mid-summer days. If the earth 
were uniform in its orbital motion, the two mid- 
summer days at the equator would divide the 
year into two parts of exactly the same length of 
absolute time. But, in consequence of the orbit 
being an ellipse, with the sun in one of the foci, 
the motion is more rapid in the perihelion half 
of the orbit, which answers to the winter half- 



UNIFORMITY OF ROTATION. 265 

year in the northern hemisphere, than it is in the 
aphelion half, which answers to the summer 
half-year in the same. In consequence of this, 
the two halves of the year, as reckoned from 
equinox to equinox, are not of the same length. 
We have every reason to believe that the earth's 
diurnal rotation is perfectly uniform, — that is, it 
takes place in exactly the same duration of abso- 
lute time, whether the earth be more near to the 
sun or more distant from it. We infer this from 
the fact, that the rotatory motion belongs wholly 
to the earth itself, and is not in any way influenced 
by the sun ; and consequently, distance from that 
luminary, however it may itself change, can have 
no effect upon this motion. We have, indeed, 
no means of verifying this fact other than that 
our well-regulated time-keepers keep the same 
rate with it, for it is in itself our primary standard 
of time. Still, both the agreement of the time- 
keeper with it, and its being a function of the 
quantity of matter in the earth only, which we 
cannot possibly imagine to be changed as a whole, 
we conclude, with as much certainty as we can 
have upon a mixed subject, that this our standard 
of time, in estimating seasons, as well as in the 
nicer divisions by which we regulate our engage- 
ments, is perfectly uniform. 

If we regard the length of the day as uniform, 
estimate the length of the year at 365 days with- 
out the fraction, and count the time from equinox 
to equinox, as ascertained by actual observation, 
we find that the summer half-year is eight days 
longer in the northern hemisphere than the 
winter half-year ; and, as the seasons in the two 
hemispheres are exactly the reverses of each 
other, it of course follows, than in the southern 
23 



266 THE TWO HEMISPHERES. 

hemisphere the winter half-year is eight days 
longer than the summer. 

This difference of solar action upon the two 
hemispheres in the alternating halves of the year, 
would have a considerable influence upon their 
relative temperatures, even though the surfaces 
of both were perfectly uniform, and exactly the 
same ; and this effect would be, to throw the 
parallel of greatest average annual heat to the 
northward of the equator. But the different 
characters of the two hemispheres, as we have 
attempted to describe them, tend greatly to in- 
crease the difference of solar action upon them. 
The northern hemisphere contains a great breadth 
of land, either immediately within the tropic, or 
at very little distance from it; and, in the eastern 
hemisphere especially, this land is, to a great ex- 
tent, dry and sandy, and of the very character 
which renders it most susceptible to solar action. 
Therefore, the northern hemisphere is much 
more heated during the northern summer than 
the southern one is during the opposite season. 

The southern hemisphere, too, though the polar 
part of it is in some measure cut off from that 
near the tropics, by the circulating currents which 
we have mentioned as revolving freely round by 
the southern extremities of the lands, is altogether 
a surface less susceptible of heat than the northern 
hemisphere ; and therefore it is more given up to 
the uniform action of the sun, the chief operation 
of which, over the wide surface of the seas, is to 
cause an evaporation ; and the general set of the 
atmospheric current is northward, or, in conse- 
quence of its being affected by the two motions, 
north-westward, for more than half of the year. 
The centre towards which this current tends is 



THE TWO HEMISPHERES. 267 

the parallel over which the radius vector travels, 
— that is, where the sun is vertical at the parti- 
cular season. From what we have already said, 
both as to the character of the northern hemis- 
phere and as to the duration of the northern 
summer, this parallel is more in the northern 
hemisphere than in the southern ; if we take the 
average of the year, the current from the south 
may be stated as reaching to the northward of 
the equator. 

But this current is so much affected by the 
characters of the several lands, that it is different 
in almost every longitude, and in many instances 
it is turned into a direction different from what 
we should expect, if we did not carefully examine 
the different surfaces, and the variations of the 
sun's action upon them. 

Were it not for those local causes, we might 
describe the state of things as being a current of 
the atmosphere from the southern hemisphere, 
and another, but a weaker current, from the 
northern, moving along the surface of the ground 
toward the parallel of greatest heat for the time, 
ascending there by means of that greatest heat, 
cooling as their mingled mass rises higher above 
the earth's surface, both on account of the expan- 
sion from the smaller pressure of the higher at- 
mosphere, and from less of reflected and radiated 
heat from the earth. 

Wherever the parallel of greatest heat is situ- 
ated, we are to understand that the current from 
the northern hemisphere, or from that portion of 
the earth which is north of the parallel directly 
under the sun for the time, always has a higher 
temperature than the current from the south. 
This arises from the average characters of the 



26S THE TWO HEMISPHERES. 

two hemispheres, without any regard to those 
local causes by which the general action is mo- 
dified, but we have already mentioned, that when 
two currents of air of different temperatures, and 
each saturated with as much humidity as it can 
carry, come together, the compound which results 
from their mixture is never capable of holding in 
solution the same quantity of moisture as was 
held by the two separately. Therefore, where 
the currents from the two hemispheres meet, 
there is a constant tendency to the formation of 
clouds, and the fall of rain; and, as the southern 
current passes for most of the surface over the 
sea, we may state that, though it is colder, and 
consequently has less evaporative power, than 
the northern current, it has the advantage of more 
evaporable matter, which, in all probability brings 
the two to an equal saturation with moisture. 

When the sun is nearer the equator, and the 
declination is changing at the most rapid rate, the 
action of those currents upon each other shifts 
most rapidly in latitude, though at this time it 
affects the two hemispheres more equally than 
when the sun is near either of the tropics. 

When the sun is near the southern tropic, the 
action upon the whole surface of the earth may 
be considered a minimum, as the sun then appa- 
rently tr.xvels round the surface which is least 
affected by its action. The southern summer 
may thus be stated as the time of greatest repose 
for the whole earth. Generally speaking, the 
effect of this season upon such of the southern 
lands as are of considerable breadth, and not much 
elevated, is to burn them up with drought ; for, 
as their surfaces get heated, the south wind, or 
south-east wind, which then blows upon them, is 



SUN ON SOUTHERN TROPIC. 



269 



rarefied by the increased heat of the surface, and 
converted into a drying wind. In the small 
islands this is but little felt, but it tells very 
strikingly upon Australia, the southern part of 
Africa, and the plains of South America. Over 
a great extent of these countries, vegetation 
withers during this season; and the grasses or 
the deciduous trees of our climates could not 
exist. Hence, much of the vegetation is totally 
different, not only in its external appearance, but 
also in its internal structure. The whole of our 
native trees perform the labour of the season 
external of the wood, and just between that sub- 
stance and the bark, where a new layer, both to 
the wood and to the bark, is formed in every 
year of the growth of the tree, and when a tree is 
no longer able to perform this annual function, it 
dies. 

Some of the southern trees, and trees of the 
middle latitudes, (for this influence extends as far 
as the northern tropic, or beyond it, according to 
circumstances,) have this habit; but then they 
are fortified against the excess of heat and drought 
much in the same manner as the pines of the 
arctic lands and the mountains generally, in the 
northern hemisphere, are so fortified ; that is, 
they have the bark smooth, and either covered 
with an impervious epidermis, or giving out in 
small quantity some matter which evaporates 
with great rapidity, so as actually to produce a 
condensation of water from the air, which, though 
imperceptible to the eye, tends greatly to the 
nourishment, or at all events to the refreshing, of 
the tree. The leaves also partake of one or other 
of those qualities; and, generally speaking, the 
trees do not labour so hard in the production of 
23* 



270 TROPICAL 

their fruit, for though there are generally succes- 
sion crops upon them, they take a full year or 
more to bring each of these to maturity, after the 
appearance of the flowers. Such trees are always 
in leaf, and where the earth is sufficiently rich to 
support them, they throw a protecting shadow 
over the ground, which really shelters it more 
from the vertical sun than our trees do from the 
slanting sun of our climates. It is not in the 
regions of extreme drought, the exposed plains 
which are subjected for months to the intensity 
of the sun's action, that we meet with trees of 
this description. In such places the ligneous 
vegetation consists in general of hard and prickly 
bushes, which are stript of their leaves in the 
intensity of the drought; and in many places 
indeed, such bushes, and also many of the trees, 
are leafless, the functions of leaves being perform- 
ed by enlarged foot-stalks, which have much of 
the strength and power of resistance of timber, 
and none of those characters which we are accus- 
tomed to regard as properly belonging to, and 
being descriptive of, a leaf. In more favourable 
situations, however, wc meet with evergreen trees 
which elaborate, in part, their own moisture out 
of the air, by the evaporation of peculiar matter, 
and it is owing to the evaporation of this matter 
that such forests are so richly perfumed. 

We find a verification of this, by attending to 
the progress of our own seasons. In winter the 
fields and the forests are scentless, or the smell 
which they emit is simply that of fresh mould, of 
the withered blade, or the decaying leaf. When 
Spring comes, and touches every little bud with 
his pencil of emerald, calling them forth from 
those swaddling clothes by which they were 



VEGETATION. 271 

shielded from the winter, and bidding them ex- 
pand and perform their labours, and adorn the 
summer, there is freshness; but we cannot posi- 
tively say there is fragrance, until the season 
advances and the blossom is put forth. In fact, 
by an attentive examination of the appearances of 
the year around us, and by comparing each effect 
with its cause, and remarking how perfectly all 
the beings, and all the agencies which we observe 
in nature, answer to each other, and promote the 
grand purpose of the whole, we should really 
derive more pleasure, and more instruction, not 
respecting our own neighbourhood merely, but 
respecting almost every spot on the surface of 
earth, than from all the volumes that have been 
written, or that can be written, upon the subject. 
From these few hints it will be perceived, that 
our deciduous vegetation, such of it as attains a 
growth sufficient for forming a sheltering mantle 
for the earth, works at the surface, and as near 
the solar action as possible; that great part of the 
seasonal action is in leaves, of which the epider- 
mis is thin, so that they suck up humidity like 
sponges, and, on the other hand, are soon withered 
away by the drought, or nipped by the frosts ; but 
that the trees of the polar regions, and of our 
mountains, have leaves with a fine epidermis, 
which probably absorbs little or no moisture, 
and is just as unsusceptible to the alternations of 
heat and cold to which they are subject ; and that, 
in those trees of tropical countries which grow 
at the outsides, there is perhaps greater firmness 
of epidermis ; and there are other means by which 
they are enabled to resisit the drought, though 
trees of this character, although abounding in all 
the more favoured spots of the intertropical 



272 DECIDUOUS TREES. 

countries, are not the typical trees. These last 
are the palms, the tree-ferns, and several other 
races, which do not grow by an increase of sub- 
stance at or near the outside ; but consist of a 
successive production of what are commonly 
called leaves, but which are in reality not leaves, 
in the sense in which we apply that term to the 
annual covering of the forest trees. They are, 
more strictly speaking, fronds — " green expan- 
sions" of the tree itself, and not separate organs, 
to assist in the elaboration of other matter. A 
plant of this kind usually rises with the same 
thickness of stem which it is to preserve while it 
lasts; and this stem is elongated by growth at 
the top only, upon which there is a large, and 
often an exceedingly beautiful crown of the fronds, 
in the centre of which is the single bud of the 
tree, protected from the heat, not only by the 
thick investment of the more advanced portion 
by which it is surrounded, but generally by a 
great quantity of liquid sap,— a quantity so great, 
that the inhabitants of such countries tap it off by 
gallons, and prepare it either as a cooling, or as 
an intoxicating,liquor,according to circumstances. 
Those palms are often exceedingly majestic in 
their appearance, and attain a greater height than 
any other trees, excepting, perhaps, some of the 
pines on the west coast of North Ameriea. They 
are also the most durable of trees. Their leaves, or 
fronds, consist of long fibres, which are remark- 
ably tough : the epidermis of many of them is 
not only hard and tough, but in some it is abso- 
lutely cased with an armature of flint. Their 
tall stems are branchless, and, considering their 
strength, they are exceedingly flexible and elas- 
tic ; so that they bow their splendidly crowned 



PALMS. 273 

heads to the violence of the weather, or stand 
armed amid the burning heat with perfect im- 
punity, and thus live to record more revolutions 
of the earth in its orbit than the most ancient and 
stately oaks of our forests. The palm is, indeed, 
often used as the emblem of immortality, as well 
as of victory — of triumph over time, as well as 
triumph over enemies ; and when we consider 
the multitudes of the human race which subsist 
upon the fruit, or the farinaceous substance of 
those stately trees, the numerous uses -to which 
the wood and the fronds are applied, the beauty 
when growing, and the durability, both against 
decaying nature and casualty in art, we may well 
cease to wonder that this family of trees should 
have, in all ages, claimed the attention and drawn 
forth the admiration of mankind. 

When the sun is over the southern tropic, — 
that is, when it is midsummer in the southern 
hemisphere, — the action of the sun in the north- 
ern hemisphere is necessarily the least possible, 
and the greatest portion possible of its polar zone is 
given up to the dominion of the winter's cold. 
The empire of this cold does not, for the reasons 
which have been already stated, range on a paral- 
lel of latitude, but forms an irregular line, being 
farthest to the north on the west of Europe, 
ranging more southerly as one proceeds eastward 
into Asia, and probably having its most southerly 
limit in North America as far to the south in 
some places as the forty-fifth degree, or middle of 
the quadrant ; whereas, on that part of western 
Europe which meets the current from the At- 
lantic, it may be reckoned about 20°, or 1400 
miles farther to the north. Within this irregular 
zone, where the cold may be said to hold unbro- 



274 NORTHERN 

ken sway during several months of the winter, 
there is a portion of the year which is perfectly 
tranquil, without cloud, without wind, or without 
alteration of any kind, In the early part of the 
season, when the snow comes, it comes with 
great violence ; but the frost soon gets so intense, 
that it congeals every particle of moisture in the 
atmosphere ; and as dry air is a very bad con- 
ductor of heat, there is much less inconvenience 
felt from the severity of the cold than from a 
much less intense degree of cold in lower lati- 
tudes. The snow also gives to the marshy 
grounds the same consistency, and the same uni- 
formity of surface, as the rest of the land ; and 
therefore, as the inhabitants are largely supplied 
with the fur of animals, to protect them from the 
immediate action of the cold, the winter in those 
regions becomes the grand season of friendly in- 
tercourse and conviviality ; and even in places 
where the thermometer is to be for months be- 
low the freezing point, the people long for the 
winter, as the season of enjoyment. Nay, even 
the Esquimaux, in their oven-shaped huts, formed 
of masses of snow, in the same manner as we 
build houses of brick or of stone, feel this season 
not at all uncomfortable. The all-provident sea 
furnishes them with an abundance of oil, which 
they burn in their lamps, and near the heat of 
which they are comparatively comfortable, re- 1 
posing on their thick matting of skins, though 
the bedstead under them is of unthawed snow ; 
and the walls, ceiling, and door of the hut are of 
the same material. Even in places much farther 
to the south, where there is not every year an 
unbroken period of winter, when such a period 
comes, it has its advantages ; and there is a plea- 



WINTER. 275 

sure in moving about the country, and also a 
healthiness, which are unknown in the more open 
winters. 

In those latitudes which are without the do- 
minion of the confirmed winter, and yet not so 
high as to be exempted from all wintry influence, 
this particular season is in general very variable; 
nor is it difficult to see why it should be so. The 
people of such places are not under the govern- 
ment of any one power. They are alike the 
subjects of the cold and the sun; and, as is the 
case with all who have to serve two masters, they 
are obliged to submit to the sway of the one 
whose turn it is to have the ascendant. In such 
places, it is impossible to lay down any general 
rules by which we can judge of what this season 
may be ; neither can we state the latitude at which, 
on any longitude, this variableness of the winter 
shall be a maximum ; for the boundary of the 
zone of winter's sway is so irregular, that the 
position of it is a matter of observation, and not 
of theory ; and, as this is the point at which, on 
the average of the year, local causes have the 
greatest influence, we cannot, from the experience 
of one year, infer, with any thing like certainty, 
what shall be the character of the next. 

We have mentioned that the sun's daily change 
in declination is very slow, near the tropics, com- 
pared with what it is near the equator ; and in con- 
sequence of this, the tropical part of the year is 
the period of steady weather, whether we regard 
the hemisphere in which it is summer, or that in 
which it is winter. Thus, in the case of the sun 
being over the southern tropic, while the north- 
ern lands are, as has been mentioned, given up to 
the quiet dominion of cold, the southern lands 



276 WEATHER AT THE TROPICS. 

are scorched and burnt up by an excess of heat. 
Under this state of things, those southern lands 
heat, rarefy, and send into the upper atmosphere, 
the air over them, and that air is replaced by the 
colder air from the sea, both to the northward and 
to the southward of the parallel of greatest heat. 
Thus, in Southern Africa, and the plains of South 
America, and, generally speaking, also in New 
Holland, there is a south or south-east wind, with 
continual burning drought. This is severely 
felt in Southern Africa, notwithstanding that the 
wind there blows from the south-east or wholly 
from the sea ; and it is also comparatively severe 
in South America, so much so as to burn up the 
plains. This is not confined to the regions of the 
equator, but extends to countries considerably to 
the north. In America it reaches not only to the 
central plains, between the sources of the great 
rivers, but also to the narrow part of the country, 
to the West India islands, and also to the coun- 
tries immediately to the westward of the valley 
of the Mississippi, all of which are burnt with 
drought during this the southern summer. Nor 
is its influence confined to the American conti- 
nent ; for it is perhaps more perceptible in the 
eastern one, the southern parts of which are of a 
more arid character, and therefore more easily 
heated. The ease with which Central and North- 
ern Asia are cooled, during this, their winter, 
tends still to augment the same effect : and the 
Mediterranean co-operates in carrying this effect 
into Africa. The air from the cooled land of 
Central and Northern Asia, and that from the 
Mediterranean, are carried southward ; and as 
both pass over much warmer surfaces than those 
which they leave, they become drying winds. 



SOUTHERN SUMMER. 277 

Thus in all parts of the earth which may be said 
to be under the direct and immediate control of 
the sun, the southern winter is the rainless season ; 
and on this account also, as well as on account of 
its being the season of minimum effect of heat 
upon the earth generally, it is the season of the 
least action of Nature in all her kingdoms ; and 
if we could imagine the possibility of the sun 
constantly revolving round the southern tropic, 
the economy of nature would very speedily be 
changed, and all the southern and intertropical 
parts would be burnt up, while the northern polar 
zone would be abandoned to extreme cold ; and 
the only habitable zone of the earth would very 
soon be that which lay intermediate between the 
action of the sun and that of the cold, and from 
the nature of things, the burning desert on one 
hand and the polar ice on the other, would gradu- 
ally encroach upon the opposite sides of this zone, 
till the remains of its fertility were also destroyed. 
Thus we see the advantages which the earth de- 
rives from its oblique motion in its orbit, by 
means of which seasons of productiveness are dis- 
tributed over the greater part of its surface, while 
the two hemispheres, from the difference of their 
characters, are still enabled to act in opposite 
ways at different seasons ; and thus carry both 
the sun's influence and the fertilizing humidity 
which this influence puts in motion in the direc- 
tion of the meridian, or north and south ; and ? 
this being done, the difference of motion in rota- 
tion in the different latitudes turns the current into 
oblique directions, by means of which the bene- 
ficial effects are further increased. 

We are not in possession of all the necessary 
information for knowing what is the specific ac- 
24 



278 ANTARCTIC ZONE. 

tion in the ani arctic, or southern polar zone, 
during the height of this, its summer, because 
that zone has not been so completely examined 
as the corresponding zone in the north. But the 
formation of icebergs, their great size, and the 
comparatively low latitudes into which they float, 
lead us to conclude that there must be within this 
zone rocky lands of considerable elevation above 
the mean surface ; and the researches which have 
been made in recent times, especially to the south- 
-ward of America, in so far corroborate this view 
of the case, which indeed must be the true one, 
wherever those antartic lands may be situated. 
We know of no means by which an iceberg of 
the dimensions of those observed off the Cape can 
be formed, but by the depositation of a vast quan- 
tity of ice and snow upon a high and rocky 
shore during stormy weather, and its detachment 
thence by the action of the summer heat. We 
know that the icebergs of the northern hemi- 
sphere are produced in this manner ; and that 
the largest ones come from the high lands on the 
shores of Baffin's Bay ; and as the southern ones 
are both larger in volume, and float into lower 
latitudes, than the northern one's, we may rea- 
sonably conclude that they are formed in the 
cliffs of more high and rugged lands. 

We have said that in this hemisphere the polar 
action is, in a great measure, cut off from the 
tropical, by means of the current which sweeps 
round the entire circumference to the southward 
of the continents; but still this current cannot 
influence very much the gravitation of the whole 
mass of waters in the sea. Therefore we may 
suppose that the snows which are piled upon the 
antarctic lands, whatever these may be, and also 



ICEBERGS. 279 

those which are accumulated in hummocks upon 
the annual part of the ice, must, when they melt, 
occasion a superabundance of ocean water there, 
and a consequent motion of that water in the 
direction of the equator, Farther, as it appears, 
both from theory, and from all the direct infor- 
mation which we have, that the general accumu- 
lation of ice at the south pole is greater than that 
at the north, we may reasonably suppose, that the 
set of the sea current toward the tropical parts of 
the earth must be greater in the southern hemi- 
sphere than in the northern. It is this, in fact, 
which produces the circulating current to which 
we have so frequently alluded : for if there were 
no motion of the south polar waters into a lower 
latitude, which had a quicker motion in rotation 
than the places at which they were melted out of 
the ice and snow, there would be no means of 
putting in motion any westward current in the 
South Seas. 

During the intensity of this southern summer, 
there is, generally speaking, a dry south wind 
upon all the three southerly lands, though it is 
much less felt in Van Diemen's island, from its 
insular situation, and in Patagonia, from the di- 
versity of its surface and the elevation of its 
mountains. In those tropical countries which 
lie to the northward of the equator, the prevail- 
ing wind at this season is, on the other hand, 
from the north. From Southern Asia, this 
current of the air is drawn by two powerful 
causes, or rather by one powerful cause acting in 
two different regions, the one situated to the 
south-west of it, and the other to the south-east, 
both nearly equi-distant from the south of Asia, 
and from each other. There are Southern Africa 



280 ASIA, AFRICA, AUSTRALIA. 

to the westward, and Australia to the eastward ; 
and while their parched and burnt-up surfaces are 
at this season sufficient to convert into a drying 
wind the atmosphere which moves toward them 
fully charged with humidity from the Great 
Southern Ocean, they also influence the set of the 
winds as far as the Himalaya mountains, and their 
continuation in Southern Asia. Europe is cut 
off from this action by the Mediterranean, the 
mountains of Atlas, and the Great African Desert, 
and the greater part of Europe is cut off from 
even the Mediterranean action by the Pyrenees, 
the mountains of central France, the Alps, and 
their continuation. We may also add, that Asia, 
to the north of the Himalaya and their continua- 
tion, which extends, with little interruption, to 
the narrow seas which separate it from Europe, 
is in like manner cut off from that action which 
takes place between the two hemispheres ; and 
thus it also is, in a great measure, given up to its 
own local climate. In Egypt, however, which 
opens by the valley of the Nile as far to the 
southward as the mountains of Abyssinia, there 
is, at this season of the year, a continual set of 
the air, or blowing of the wind, from the north. 
Thus, though there is much less land in the south- 
ern hemisphere than in the northern one, and 
therefore much less action of the sun during the 
southern summer than during the northern, there 
is still a great tendency of the air toward all the 
broader lands in that hemisphere ; and they are 
much more parched, or have drier seasons, than 
any of the lands in the north, excepting such as 
are permanently desert. 

In America, to the eastward of the Stony 
Mountains, there is nothing material to interrupt 



AMERICA. 281 

the invasion of the polar winter during this season ; 
and therefore we find a cold winter extending 
south the valley of the Mississippi to a much 
greater extent, that is, into a much lower latitude, 
than we find in Europe. At the same time, the 
plains of the southern and intertropical parts of 
America are burnt up. 

But after the midsummer in the southern he- 
misphere has passed over, and the sun declines 
toward the north, bringing into the northern 
hemisphere that greater degree of solar action of 
which we have mentioned that it is susceptible, 
the state of things changes ; and the change is 
accompanied by a general depositation, over the 
southern and tropical parts, of the moisture which 
the atmosphere has evaporated, and hitherto held 
in solution ; and in this return of the season, we 
may say that, the more southerly the places are, 
the rain falls on them with the greater violence, 
provided that they are of sufficient breadth and 
uniformity of surface to be out of the operation of 
local causes, as between sea and land. 

The times at which these rains commence in 
different places depend, in some sort, upon local 
causes; and they are sometimes brought directly 
by the sea winds which accompany the sun in 
its northerly declination, and sometimes by the 
returning current, as the surface of the southern 
land cools. In all cases, however, it is evidently 
the land which puts those currents originally in 
motion, that is, the action of the sun upon the 
land, either by arriving and heating, or by with- 
drawing and leaving to cool. Thus, in India, 
the south-western monsoon, which begins not 
long after the spring equinox, breaks first on the 
more northerly parts of the Malabar coast, show- 
24* 



282 RAINY MONSOON. 

ing that this direction is given to the air by the 
ascent of the atmospheric volume over the dry 
plains and deserts of Northern India, which have 
now been long subjected to burning drought; and 
as we advance farther and farther south along the 
Malabar coast, the setting in of this rainy season 
is later and later. At the commencement, that 
is, during part of April and May, this current of 
the atmosphere can hardly be said to amount to a 
steady and constant wind ; but it is so during 
June, July, and August, about the end of which 
latter month it begins to fall off. When it first 
breaks, it is accompanied by violent thunder, 
lightning, and rain ; but these slacken as it ad- 
vances, and before its termination they cease 
altogether. In October the current is reversed, 
and an opposite wind blows strongly from the 
north-east, continuing till about the end of De- 
cember, or the depth of the southern winter. 
This north-eastern monsoon is occasioned by the 
great cold, and consequent pressure and conden- 
sation of the air upon the Himalaya mountains 
and the adjacent country, at the same time that 
the lands to the south are again beginning to get 
warm. 

In Southern Africa, almost the entire summer 
half-year is perfectly dry, with a wind from the 
south ; and the rains do not set in till the return- 
ing current, about June and July; but their 
violence is generally very great. Throughout 
the rest of Africa there are rains nearly at the 
same period of the year, but perhaps a little earlier 
in the places which are farther to the north ; and 
as that part of the country which lies immediately 
north of the Gulf of Guinea, and may be said to 
be bounded on two sides by the sea, and nearly 



DRY MONSOONS, 283 

on the other two by the Senegal and the Niger, 
is subject to a sort of oblique action of the air 
between Sahara and the southern deserts, there 
are some differences in its seasons of rains. 

In America, that is, in the parts near the tro- 
pics, where the seasons consist of an alternation 
of rain and drought, the times do not differ much 
from those on the eastern continent; only, as 
there is no land to answer to South America, and 
occasion monsoons, the rains proceed more regu- 
larly over that country ; but as far as seasonal 
rains do reach to the northward, they accompany 
the northward motion of the sun. 

When we get without the range of this tro- 
pical influence, the equinoxes are the times of 
variable weather; because it is then that the 
surface is most exempted from the influence both 
of the summer sun and the winter cold, and local 
causes are enabled to produce the most conspi- 
cuous effects. So also in those countries which 
are subject to monsoons, or other alternations of 
rain and drought, it is always at the turn of the 
monsoons that the weather is most violent. It 
is always in situations where the monsoon, or 
other periodical action, is liable to the greatest 
interruptions, that those times of change are 
marked by the greatest violence and disorder of 
the weather. In latitudes which are comparatively 
high, we find that there is generally an atmo- 
spheric disturbance some time near the equinox, 
and every one must have heard of equinoxial 
gales. Those gales do not, however, happen at 
the times when day and night are equal ; because 
the causes upon which they depend require some 
time to produce their effects, and the times so 
required must always be in proportion to the 



284 CHANGES OF MONSOONS 

resistance with which the cause meets. Thus, a 
country which has a uniform surface of consider- 
able extent will resist every change much longer 
than one of which the surface is irregular, and hi 
consequence of which the weather is never very 
steady. In consequence of this resistance, we 
have the changeable weather at a greater or less 
time after the astronomical period of the equinox ; 
and the violence, or, at all events, the rapidity, 
with which the change takes place, is always in 
proportion to the resistance with which the cause 
producing the change meets. Thus, in England, 
where the weather is not very steady at any sea- 
son, those changes are not rapid or violent ; and 
there is often a long struggle of alternate summer 
and winter, both after the vernal equinox and 
after the autumnal. In countries farther to the 
north, however, and of which the surface is more 
flat and uniform, the changes are far more rapid ; 
and in some of the polar countries, where the 
snows do not dissolve till the year is considera- 
bly advanced, the transition from winter to sum- 
mer is so rapid that there can hardly be said to 
be any intervening spring ; while at the turn of 
the year there is an equally brief duration of what 
we call autumn, and winter follows closely on 
summer, so closely, indeed, that the standing 
crops are often buried in the snows. There is 
another peculiarity of those northern countries, 
and that is the uncertainty of the two great sea- 
sonal changes, which are comparatively regular 
in places nearer to the equator. The reason of this 
is the comparatively weakened action of the sun, 
and the consequent strength of local causes, in 
consequence of which the particular train into 
which the weather has run is not so easily broken 



AND SEASONS. 285 

as in places where the influence of the sun is 
more powerful. 

Such are a few of the leading particulars by 
means of which some judgment may be formed 
of the general features and economy of our pla- 
net ; but the subject is one of great extent, and at 
the same time involving many uncertainties and 
difficulties. It is impossible for us to say of how 
many of the elements we may be entirely igno- 
rant ; and of those of which we have some know- 
ledge, very many are but imperfectly understood, 
so that they demand much more intimate obser- 
vation before we can speak positively respecting 
them. 

The hints which are given in the preceding 
sections will show both how the general elements 
of a rational knowledge of the earth may be ac- 
quired, and how we are to use them as instru- 
ments of knowledge. Had space permitted, it 
would now have been our business to proceed 
with an examination of the three classes of beings, 
which make up the observable part of the earth, 
namely, minerals, plants, and animals. But the 
introduction of these, even in the most imperfect 
manner, is inconsistent with our limits ; and 
therefore we have considered it more useful to 
take a survey of the earth as a whole, — to ex- 
amine the habitation with sufficient breadth of de- 
tail for comprehending its general characters, 
rather than to give a mere dry catalogue of its ac- 
commodations and of all the creatures by which it 
is tenanted. There is, however, so close a con- 
rexion between the greater movements of the 
earth, and of the waters and air upon its surface, 
and the characters of all its growing and living 
productions, that if we are able to excite a desire 



286 CONCLUSION. 

of knowing the one, a desire of knowing the 
others will follow of necessary consequence. In 
order to stimulate this desire, it requires no argu- 
ment to prove that the earth itself is the first sub- 
ject of our study, because it serves as a kind of 
artificial memory of all the rest ; so that, if we 
once know the earth well, it will enable us to 
bear in mind the characters of its component 
parts and its inhabitants, as occasion makes us ac- 
quainted with them. And we may say, without 
fear of contradiction, that he who has made him- 
self well acquainted with the general structure 
and economy of the earth, has laid a surer foun- 
dation for knowledge, — not only extensively and 
practically useful, but knowledge which has a 
vital principle in it, and will grow in the contem- 
plation, — than could be laid by the study of almost 
any other subject. 

Nor, if we enter upon this study with a right 
mind, in the earnest and honest desire of truth, 
and with a disposition to turn this truth to the 
greatest possible advantage, can we fail in being 
both morally and religiously the better for it. In 
this subject we find displays of wisdom and good- 
ness which are far beyond any that we can meet 
with in the details of single objects upon the 
earth, however wonderful, or however beautiful, 
these may be in themselves ; and when we are 
enabled to observe with what perfect conduce- 
ment to the general good, seas and lands, moun- 
tains and valleys, deserts and fertile regions, and 
hemisphere with hemisphere, co-operate with 
each other, it is impossible for us to avoid per- 
ceiving, and feeling with no common delight, 
that " the earth is full of the glory of the Lord." 



Lr Mr'33 



